Experience
in a Book
Electrical
System
COLOR CODING: In electrical diagrams, this book
uses the same wire color coding scheme as Jaguar uses in
their manuals. If two colors are indicated, the first is the
base and the second is the stripe. If three are indicated,
the third is a spiral stripe. The color codes are as
follows:
N - browN (not neutral!) - usually 12V
power
B - Black - usually ground
U - blUe
K - pinK
S - Slate (British for gray)
G - Green
Y - Yellow
O - Orange
R - Red
W - White
P - Purple
Jaguar also throws an L in occasionally to indicate a
Light color.
WIRING DIAGRAMS: If you're going blind staring at
the diagrams in the owner's manual, Michael Frank sends this
tip: "Wiring diagrams in the following sizes (prices in
British Pounds):
500mmx353mm £9.95 + £1.50 postage
594mmx420mm £12.95 + £2.00 postage
840mmx594mm £19.95 + £3.00 postage
1180mmx840mm £34.95 + £4.00 postage
Available for most classic Jags, with XJ and XJ-S
available soon. The diagrams are laminated in plastic and
color coded to match the actual wiring. The supplier is:
Classic Graphics
11 Springhill Grove
Stockton, Cleveland TS17 OYW
England
Dan Jensen adds another option: "I called Jaguar Services
(page *)...They stated they
have the license to sell copies of the Jaguar wiring
diagrams. Price is $20 each for "two-door" models (XJ-S I
assume) and "four doors" (S3 I assume) covering the years
thru 1987. In later years they apparently have diagrams for
each year. They assured me that these were not the
wiring diagrams in the owners manual, Haynes, etc., but
approximately 25 pages of very specific
drawings/details."
Regarding these wiring diagrams, Mike Wilson says, "They
now come with a Supplement that includes corrections for the
following:
Fig 2.1: Added Diode to Neutral Switch
circuit
Fig 2.2: Added Diode to Component location
Fig 6.2: Added Shorting Plug behind Fog Light Relay
Fig 11.1 & 12.1: Corrected the Titles for Coupe and
Convertible
Fig 15.1: Ground Code Correction for heated rear
window
Fig 20.2: Cruise Control, Resume switch and set switch
locations reversed
Fig 22.1: Door Lock Terminal Identification added
Fig 25.1: Added Diode to EFI and Emissions diagram
Fig 25.2: Added Diode component location
Fig 6.1: New wiring diagram for Fog Lamps
Fig 20.1: New wiring diagram for Cruise Control
Both publications are numbered: S-57/90."
OPTICAL FIBERS: If the wire is solid dark gray, it
may not be a wire; it might be an optical fiber.
Illumination of the air conditioning control panel is via a
single light bulb in a housing in the console, with the
light carried by fibers to the various locations. This makes
the whole panel dark with a single bulb failure, but it's a
cinch to replace the bulb; just remove the top cover of the
console (3 screws) and replace the bulb inside the
housing.
Don't cut those fibers; they're not easy to splice. They
are a little brittle, so don't bend them too sharply either.
They tend to get in the way when working on the radio, so be
careful.
If you need to disconnect one from the fixture at either
end, don't just yank. Insert a tiny screwdriver into the
slot along the side of the socket and twist to spread it a
little, and the fiber will come out easily. It has a little
brass fitting on it with a lip. To put it back, simply press
it in until it clicks.
Note that the sockets on the bulb housing are not all the
same. If you open it up and look inside, you will note that
some of the sockets feature a colored filter. Which socket
used will determine what color light comes out the end of
the fiber.
If you need to try to splice a fiber, Don Mathis of the
Lightguide Media Department at AT&T Bell Labs says: cut
the ends of your plastic fibers with a razor blade. This
should give a very smooth cut. You need to butt the two
fibers together while you epoxy them in that position. A
"V-groove" works well. If you come up with a means of
clamping the two fibers together mechanically, index match
grease between the ends helps to decrease the loss. Silicone
grease, clear, works well. Vaseline is not bad either.
If all else fails, Edmund Scientific has the fiber for
approximately $.70/foot for 0.040" diameter. You can also
get genuine Jaguar fibers from several mail order outfits,
but they aren't cheap.
WIRE SPLICING: Making durable, reliable wire
splices is essential to working on a Jaguar; there are a
great many electrical circuits, they tend to be rather
complicated, and the Lucas components cause enough trouble.
When troubleshooting, it is important to be able to
eliminate a previously-made splice as a possible fault.
First, it is helpful to have a pair of wire-stripping
pliers around -- a good pair. A good wire stripper
will remove insulation from the tip of a wire neatly, doing
much less damage to the conductors than you can do with a
razor blade, or your teeth, or whatever. However, a cheap
wire stripper, especially one in which the stripping slots
don't line up properly or are not sharp enough, can cut half
the copper strands while removing the insulation.
When splicing wires together, the best way is to solder
them -- if they won't be exposed to a great deal of heat,
which may melt the solder. A soldering gun of about 140W
capacity is recommended; soldering irons are intended for
circuit board work, and do not work well doing wire
splicing. On larger wires, an iron may not provide enough
heat to make a secure connection. And, the intermittent
nature of wiring harness repair makes the instant heating of
the soldering gun a big help. Even the little light bulbs
usually found on soldering guns tend to be helpful in
automotive work.
If your soldering gun isn't heating like it should,
loosen the nuts holding the tip and retighten securely.
These are electrical connections (a soldering gun is a
transformer that provides low voltage and high current
through the tip to heat it), and they need to be
tight.
Regardless of whether the solder used says "resin core",
you should use a separate tin of resin flux. The first time
you use it, you will know why this is recommended; relying
on the resin in the solder doesn't work nearly as well. Do
not use an acid flux; it is intended for copper pipe
connections, not electrical work. And, before doing any
soldering, always dip the tip of the gun in the flux and
apply a little solder to the tip as it heats up.
Another workable splicing method, and the method to use
when exposure to heat is a factor, is to use a crimp-on
connector. If the crimp-on connector is the uninsulated
variety, it may be possible to combine methods; crimp the
connector to the wires, and then apply solder.
Crimp-on connectors can be purchased in automotive
stores, often in a package along with other types of
crimp-on terminals. Some of the connectors will have a
built-in piece of insulation, while others are bare. Keeping
a selection on hand is a must.
Most of the available electrical connectors work well,
but there are a couple specific types to avoid. One to avoid
is a tap connector that consists of a plastic device than is
placed over an existing wire, a new wire is put in place
alongside it, a slotted metal guillotine blade connector is
squeezed into place with a pair of pliers, and a cover is
folded over and snapped in place. While slick, this
connector makes weak and unreliable connections, especially
on unusual wire sizes.
Where possible, avoid the use of electrical tape. With
age, it tends to harden, while the adhesive gets gooey.
After some time, tape on connections can be found to have
fallen off or slid up the wire, leaving the conductor
exposed. If electrical tape must be used, it should ideally
be stretched a little as it's applied; the stretch will pull
it tightly around the conductors, helping prevent its coming
loose anytime soon.
Please don't use friction tape. Electrical tape is solid
plastic, while friction tape is black cloth. Friction tape
is not intended for electrical work.
If you are connecting separate ends of wire or can slip
something over the wire from an end elsewhere, the best
insulation method to use is heat-shrink tubing. Heat-shrink
tubing is available at some auto supply stores, hardware
stores, and building supply stores, but the best place to
buy it is at an electronics store. At the better electronics
stores it can be purchased in 4-foot lengths and in a great
variety of sizes. It also comes in various colors, including
near-transparent so you can see how lousy your soldering job
was.
Select a size of heat-shrink tubing slightly larger than
the insulated wire, and cut a piece a little longer than
your splice will be. Slide this piece onto one of the wires
before you connect the wires together. After soldering,
slide the tubing over the connection and use a cigarette
lighter or match to shrink it down snugly. Heat-shrink
tubing can also be used to insulate uninsulated crimp-on
wire connectors.
CONNECTORS: Since the basic wiring connectors
themselves are among the worst features of Lucas
engineering, it is recommended that the owner keep a supply
of Molex connectors (such as those sold at Radio Shack) on
hand. When a connector is intermittent or is otherwise
causing trouble, don't try to clean it up; simply cut the
sucker off and install a suitable Molex connector in its
place.
Some hardware or building supply stores carry a substance
for preventing oxidation and corrosion of electrical
connections. One such substance is called Ox-Gard, by
Gardner Bender Inc. of Milwaukee; it comes in a 1 oz. tube
and has the consistency of grease. Since Jag electrical
connections tend to corrode, it is suggested the owner keep
a tube of this stuff around and use it. The first place to
apply it is on both ends of each fuse you can find.
Tom Wagner says, "I have a number of associates that
actually grease the lamp socket base. They swear that it
keeps the moisture out and prevents rust. I have no
emperical data to confirm this and really don't have the
guts to try an experiment. I have noted however that some
cars (especially Fords) have a type of white grease packed
into the connectors. Unfortunately every time I have seen
this material it is because I have been replacing the
device, so I don't know if the device has failed due to it
or whether it is just a normal failure."
GROUNDS FOR COMPLAINT: This author has noted
several places in the XJ-S where a ground connector is
attached to the chassis with a bolt or screw that also holds
a harness strap. The harness strap is plastic, and is held
between the ground wires and the chassis. This is NFG
for at least two reasons: First, it means that the only way
the ground connection can possibly be made is through the
screw itself, which is less than half as reliable as a
properly seated ground connection. Second, since the strap
is plastic, the screw simply cannot be tightened securely,
as that would only crush the strap.
The car has enough electrical problems. It is recommended
that whenever such a ground connection is found, it should
be revised. One method is to provide two separate screws,
one for the harness strap and one for the ground. Be sure to
scrape all the paint away under the ground connection before
reinstalling it. Maybe a little anti-seize compound would
help, too -- both in assuring a good electrical connection
and in keeping the bare metal from rusting.
So far, such ground connections have been noted on the
wheel wells just behind the headlight housings on both
sides, and inside both doors near the hinge end.
SPADE TERMINAL INSULATION: In the places that the
XJ-S has female spade terminals to connect to male spade
lugs on a device -- such as on the starter relay at the
right rear corner of the engine compartment -- the female
terminals on the ends of the wires have a milky white
plastic sleeve that snaps in place over the terminal to
prevent accidental shorts. These insulators are guilty of
misleading in two different ways: 1) When the terminal is
pushed onto the spade lug on the device, the lug may enter
the insulator between the flat side of the terminal and the
sleeve rather than into the terminal itself. This may
actually feel like it was inserted properly, and will
usually provide a connection when tested -- but it will be
intermittent, and you will have problems sooner or later. 2)
When the connector is pushed onto the spade lug, the
terminal itself may slip backwards within the insulator
without being noticed. It looks like it's in place, but the
terminal itself is actually only touching the tip of the
spade lug, again making an intermittent connection.
A very workable plan is to take these insulators off and
throw them away, and insulate the female spade terminals
using heat-shrink tubing.
If you are installing new female spade terminals on a
wire, it is suggested that you use two different sizes of
heat-shrink tubing to insulate them. This works far better
than the little plastic collars that come on crimp-on
terminals, so it is suggested you rip the plastic collars
off and use this method instead. This also allows you to
solder the wire to the terminal after crimping for a more
secure electrical connection. To insulate the terminals,
take a piece of heat-shrink tubing about 1/2" long and a
diameter that will fit over the wire itself as well as the
crimp end of the terminal and slide it onto the wire before
attaching the terminal. After crimping and soldering, slide
this piece over the crimp connection and use a match to
shrink it down onto the crimp itself, leaving just the spade
terminal exposed. Then cut a piece of heat-shrink tubing of
a diameter that will fit over the female spade terminal
itself about 1/2" long and slide it on until the end is
flush with the business end of the terminal, and shrink it
in place so that it covers the terminal and overlaps the
first piece over the crimp. The end result is a two-level
insulation job that looks professional and even provides a
measure of strain relief to the wire connection.
It's possible to do a similar two-level insulation job to
a male terminal using a very short piece of the larger
heat-shrink tubing, but it doesn't surround the terminal
itself when disconnected, so unplugged terminals involve
some risk of bumping into things and shorting. It works just
splendidly when plugged in, though.
CONTACTS: Vince Chrzanowski of Baltic, CT restores
old auto radios for a living. He recommends Channel
Master COLOR contact Shield, Silicone Base, which is
available at most electronic supply houses. Model 9101 is
the 16-oz. can; model 9100 is a 6-oz. can of the same stuff.
He claims many rocker switches, even many of those that
appear to be broken, can be fixed by spraying this stuff
through the cracks without even removing the switch from the
panel!
Chad Bolles likes LPS 1. "It is greaseless and does not
attract dirt and is made for elec systems." Tom Wagner adds,
"CRC has a chemical for cleaning too."
Tom Wagner warns against confusing electrical contacts
with connectors, and using the wrong product: "My major
concern is that folk will generically use contact cleaners
without actually knowing that fuses and the like are
actually connectors. Never, I repeat, never use a
contact cleaner on them. They are for rotary switches and
will do more damage than good. Often a cleaning with alcohol
and a clean business card is all that is needed. There are
chamois on sticks for cleaning VCR heads at Radio Shack that
are excellent. Never use a Q-Tip, they will leave material
behind. For pin connectors, clean all the dirt you can out
and use alcohol followed by air to take any surface residue
out. Then a simple repeat removal and insertion of the
connector a number of times is often all that is needed.
Stubborn cases usually require more drastic means. A
typewriter eraser used gently is a very good burnisher.
Round wood toothpicks can be used to clean the female part
of sockets.
"Check for broken or cracked parts. They can also show
where failures might be; the electronic circuits very seldom
break down, but sometimes the plastic they are attached to
allows the connections to fatigue, resulting in poor
connections."
EFI CONNECTORS: The connectors that snap onto the
fuel injectors and the temperature sensors are rectangular,
hard, and have an external spring to provide snappage. These
connectors, used on Bosch and Lucas systems worldwide, are
common enough that replacement connectors are available.
POTENTIOMETERS: Tom Wagner says, "There is another
product for variable resistors like volume controls and air
position sensors. It is a pretty good "stop gap" solution
for intermittant radio controls and sensors, but has to be
sprayed directly on the carbon track. It does work, have
used it for years on noisy radio controls. Check the can and
be sure that it is for controls not switches. In the old
days we used "carbon tetrachloride" (just tapped the shop
fire extinguisher), but that wrecks your liver and can
actually be absorbed through the skin. Illegal and
dangerous!"
WIRING HARNESS RENOVATION: Richard O. Lindsay
sends this innovative method: "Tie the harness into position
with tie-wraps thereby preserving all of the original bends
and more importantly, break-out points. Remove all of the
jacket leaving the wires only in position. This is a good
time to clean and degrease all of the insulation. Then cut
each wire, one at a time, about a foot or so back from the
connector end. This cut should be well back into the jacket
away from the breakout point. This allows you to splice in a
piece of generic wire of the appropriate gauge and turn the
original cut off wire around leaving the nice clean
color-correct wire sticking out. The addition of a correct
connector makes for a functional harness that, when vinyl
wrapped, will look new and be color code correct!"
Dave Covert sends the following: "The cloth cover is not
something you can really buy, but must send your harness to
a shop and have it wrapped. The shop has a braiding machine
that weaves 32(?) strands of cotton thread around the
bundle. Sixteen strands in a clockwise direction, sixteen
strands in a counter-clockwise direction. The cotton strands
are usually black, but if your original harness had a
colored tracer thread(s), send a sample along with the
harness and the shop will switch some of the 32 strands out
for colored strands to match the original tracer. The shop
will also want you to mock up your harness with a few pieces
of electrical tape to hold it in the proper shape.
"Cost is modest, and varies a bit from shop to shop. I
had good conversations with two different shops, each with
different pricing schemes. The first shop was Class-Tech of
Bend, Oregon, 1-800-874-9981. The second shop was Harnesses
Unlimited of Oreland, PA, (610) 688-3998."
If a complete rewrap isn't called for, Bruce Snyder sends
these suggestions: "I've had a lot of success with the large
sizes of heat-shrink tubing available at electronics
suppliers. It's available in long lengths and a large
variety of diameters, and looks quite nice when installed.
Of course, you have to be able to slip it over the wires.
The other thing that has worked well for me is the dry vinyl
and cloth wrapping tape from Eastwood, and the cold shrink
tape. These work very well, and have no adhesive to make
that sticky mess we all love so well. These all take a
little time to install, but look good, are durable, are
considerable cheaper than a new harness and don't involve
extricating the old harness for re-wrapping."
RODENT DAMAGE: One of the members of the XJ-S
online discussion group happened to mention that his wiring
had been damaged by rodents, and it was simply
amazing how many members responded with similar
experiences! Apparently Lucas wiring, along with all its
other shortcomings, is found delectable by rats! The
problems usually seem to occur up in the V between the
heads; it's probably a nice, warm, cozy spot for a rat to
curl up in, and there's an assortment of tasty wires to chew
on. Simon Gray reports, "I spent yesterday replacing spark
plug leads, you guessed it, mice. It may have been a
rat, either way it took one night to eat through four cables
and totally ruin my day (I had renewed them three months
ago)." They don't limit themselves to spark plug leads,
though; there are also reports of chewed fuel injection
wiring and ignition pickup wires.
Matt Dillon suggests, "My solution was to leave a cheap
radio on in my garage all the time. Apparently the mice
don't like the noise. My radio's been on for 2 years without
any further rodent attacks. Until I started playing the
radio, my cat was attacked twice!!!"
Perhaps you should get a cat to protect your cat,
Matt.
FUSES: The UK uses a different definition of the
rating for fuses than the US does. The US rating is for how
much current the fuse will carry without blowing; the UK
rating is for the amount of current to blow the fuse within
a certain time. The difference is about 2:1. Simon S.
Johnson sends the following data: "...the source: a 1974
edition of "Buss Fuse Car and Truck List" which has on the
back cover a section call "Foreign Car Fuse Replacement
Data," -- foreign to the US, that is. It states that
"English standards differ from US standards. This accounts
for difference in ampere ratings." Then it provides a
list:
English Type
|
Buss Replacement
|
50 amp
|
AGC 30
|
35 amp
|
AGC 25
|
30 amp
|
AGC 20
|
25 amp
|
AGC 15
|
20 amp
|
AGC 10
|
10 amp
|
AGC 7 1/2
|
5 amp
|
AGC 3
|
You may find that your fuses have a little paper label
inside with both ratings; a Lucas rating (British)
and a "continuous" (American) rating.
If your car uses tubular glass fuses and the repair
manual specifies an amperage, it's in the British rating;
you will have to correct per the chart above to use the
correct American fuse.
RELAYS: There are relays all over the XJ-S. Most
are a Bosch 12V 30A SPST relay number
0 332 014 113, and are a small metal box with
spade terminals labeled 30/51, 85, 86, and 87. 85 and 86 are
the coil connections, 30/51 is the common contact, and 87 is
the Normally Open (NO) contact. The typical layout of these
terminals is shown in Figure
24.
These relays conform to a standard, and are readily
available at any auto parts store. Often, the aftermarket
relays are labelled for use in controlling driving lights,
and may be found among the driving light kits instead of
under general electrical components. They are usually
entirely black plastic, and they often have an integral
mounting lug. And of course, an aftermarket electrical
device is likely to be as good or better than a British
original (although not all -- this author found a particular
type relay made in Italy and sold at AutoZone that wasn't
worth a damn, three in a row failed quickly).
Some of these relays (and some of the aftermarket generic
equivalents) have a second terminal 87 in the center of the
base. This terminal is connected internally with the first
87; it merely serves as a second terminal to the same
contact. In most cases, a relay with the extra spade
terminal can be used to replace a relay with only one 87, as
the socket or plug will have a hole or slot for the unused
spade to protrude through. However, one should be careful
about replacing a relay with two terminals with a relay
having only one; the socket may have a wire that connects to
this spade, and will not be connected if it is not there. At
this point, the solution is usually a simple matter of
trading one relay with another to get a relay having both
terminals where it is needed.
If you are installing or relocating relays, you should
note that relays are not watertight, even when they appear
to be. Their durability will be greatly enhanced if you will
install them with the terminals pointing downward, so that
dripping water can't get in and any moisture that does get
in can drain out. Bosch relays even have a little hole in
the bottom that you can use to spray contact cleaner or some
such in there to help keep things from getting cruddy.
Unfortunately, the XJ-S is covered with exceptions to the
relay standard. Following are descriptions of several
components that look like standard relays and will
fit in the standard socket, but are not the same and
exchanging with standard relays may cause problems or even
shorts.
RADIATOR FAN RELAY: This
relay, SRB411, has the exact same layout of spade terminals
on the bottom, except that the terminal in the center is
labeled 87a. This relay is bright red -- Lucas' way of
indicating "Hey, dummy, this relay is different!" A
close inspection of the schematic on the housing shows that
this is in fact a SPDT relay, and the 87a is a Normally
Closed (NC) contact.
In this particular application the 87 contact is 12V
power and the 87a contact is connected directly to ground.
As a result, if a normal relay with two 87 terminals is
plugged in, a direct short will result and fuse #1 in the
headlamp fusebox will blow immediately.
The NC contact shorts the fan motor to ground when not
operating. It's not known why Jaguar did this. If a normal
relay that has no center spade terminal is installed, the
system seems to work fine; the fan operates normally when
on, and the fact that the fan is not grounded when off
doesn't seem to make any noticeable difference. However, it
seems unlikely that Jaguar would have gone to the effort of
supplying the grounding circuit without a good reason.
Even though a generic driving light relay won't serve
here, finding a 12V 30A SPDT relay is usually not too
difficult. If you don't wish to buy the Lucas original, you
can look for a Bosch, Hella, or Potter & Brumfield. Per
Bob Whiles, the part number for the Bosch is
0 332 204 105 and for the Potter &
Brumfield is VF4-45F11; this author suspects Bosch numbers
0 332 204 109 and
0 332 204 125 would work as well. Per Volker
Nadenau, the Hella part number is 4RD003 520-13. All of
these will plug right into the red socket. Of course,
finding a parts store employee here in Florida who even
knows what a relay is, much less whether or not it has NC
contacts, can be a challenge; "What kinda car is that fer?"
as he prepares to type on his computer terminal. Actually,
the best place to look for relays is in a junkyard; just
about all cars use relays for one thing or another, although
they are usually hidden inside fuseboxes or other
compartments. European cars often use Bosch relays. All
automotive relays seem to have a little schematic on the
outside, so it is a simple matter to confirm whether or not
a relay has the necessary 87a NC contact.
Or, you can go to an electronics store and buy a generic
"ice cube" 12VDC SPDT (or DPDT, 3PDT, 4PDT, etc.) and solder
short jumper wires to suitable spade connectors to plug into
the original socket. If you get extra contacts, just wire
them all up to provide extra current capacity.
87b: Some relays, including Bosch number
0 332 015 006 and
0 332 015 012, have an 87b terminal. This is
a second NO contact just like the 87 terminal. However,
while the relays with two 87 terminals have both terminals
connected to the same contact, this relay actually has two
separate contacts. Here's the distinction: when the relay is
energized, the same connections are made as in the relay
with two 87's, but when unenergized, the 87 and 87b
terminals are not connected to each other. In some
instances, this may make no difference, and perhaps a relay
with an 87b terminal can be used to replace a relay with two
87's, but be very careful replacing a relay with an 87b with
a relay with two 87's -- something might backfeed through
the 87 terminals on the relay and cause malfunctions.
ELECTRIC FAN DIODE PACK: Yet
another exception to the typical relay described above is
the blue item mounted on the top left side of the engine
compartment just rearward of the diagonal strut. It looks
like a standard relay, and has the same spade terminal
layout as a standard relay, but it's not a relay at all;
it's the diode pack for the electric fan. The terminals are
numbered simply 1, 2, 3, 4, and 5. You can easily pry the
box open with a small screwdriver and inspect the layout
inside.
Diodes merely allow current in one direction only. When
testing this pack, you should be able to get current to flow
from terminal 3 to terminal 1 but not the other way around.
You should also be able to get current to flow from terminal
5 to terminal 4 and from terminal 2 to terminal 4, but not
the other way on either. This description uses the accepted
definition of current as flowing "from" a + terminal to a -
terminal. Note that some meters may not incite a diode to
flow in either direction when set to a standard
ohmmeter setting; if the meter does not have a setting for
testing diodes, it might be better to use a light bulb to
test.
If any of the diodes prove bad, it's not rocket science
to replace them individually. Suitable diodes are available
at any electronics supply store; Radio Shack catalog number
276-1661 will serve nicely.
In case you haven't developed a healthy disrespect for
Lucas engineering yet, here's another example of their
handiwork: the wires that connect to terminals 1 and 3 are
both GN, but they are different and you'd better not mix
them up! Likewise, the wires that connect to terminals 2 and
4 are both LG, but don't mix those up either!
If you've already disconnected them and gotten confused:
on the author's 1983 XJ-S, the GN wire that connects to
terminal 1 is actually two wires connected to the same spade
terminal, while the GN that connects to terminal 3 is a
single wire. Likewise, the LG wire that connects to terminal
2 is actually a pair of wires, while the LG that connects to
terminal 4 is a single wire. Here's hoping other cars are
the same!
I will describe more elaborate tests, in case the above
proves inadequate. If you apply 12V to a GN wire and the fan
starts running, that wire connects to terminal 1. If the
clutch on the A/C compressor engages, it connects to
terminal 3. If the engine is cold and you turn the ignition
on and read 12V at a LG wire, it connects to terminal 2; if
not, either a fuse is blown or it connects to terminal
4.
Just when you thought you had these things figured out,
Jaguar goes and does something totally unexplainable. Michel
Carpentier reports on the diode pack in his Daimler Double
Six: "The blue box is clearly the same as described in your
book: one diode with anode in 3 and cathode in 1; two diodes
with anodes in 2 and 5, common cathode in 4. But it provides
the logic for the headlamp wash/wipe system. 2 is connected
to a blue/red wire (high beam), 5 to a blue/white wire (low
beam), 4 goes to terminal 85 of the wash/wipe relay via a
blue/red wire. 1 has a green/blue wire going to one of the
washer pump terminals. 3 has two green wires, live when
ignition is on. Terminal 86 of the headlamp wash/wipe relay
is connected to the other terminal of the washer pump
(common to windshield and headlights) and to the windshield
washer switch. When you push the windshield washer switch,
terminal 86 of the headlamp wash/wipe relay is grounded and
the pump operates via diode 1/3. If the headlights are off
you get normal windshield washer operation. If they are on
(either low beam or high beam) 4 is live so the relay is
energized: the headlamp wiper motors kick in and valves
open, squirting fluid on the outer headlights. Much ado for
a perfectly useless gadget!
"Back to the cooling fan. Against the radiator is a small
harness which comprises the following: A green/brown wire
running from a connector on the RHS of the radiator (said
connector linked to A/C compressor clutch) to terminal 86 of
the red fan relay. Somewhere in between, this wire is cut
and a small PCB (about 30x8mm) holding a diode soldered in,
with the cathode towards the relay. Terminal 86 of the red
fan relay is also connected to the thermostatic switch by a
green/white wire. A black wire connects terminals 85 and 87A
to ground. A brown/green wire comes from the main harness on
the LHS (live at all times) and goes to terminal 87. Another
small PCB (exactly 32x10mm) is also buried inside the
harness. It holds two diodes with a common cathode connected
to the thermostatic switch by a green/orange wire. One anode
has a red wire going to terminal 30/51 and thence to the fan
motor. The other anode is connected to the main harness by a
green wire (live when ignition is on). This harness is held
together by the usual weaving: outwardly there is no way you
can tell that it is so electronically sophisticated as to
contain 3 diodes!"
EFI MAIN RELAY: On the Digital P EFI system
diagrams, item #312 is the "main relay". This relay is
mounted in the trunk near the ECU, right alongside of the
fuel pump relay. Don't mix up the two relays; the fuel pump
relay is a standard relay, but the main relay, Bosch #
0 332 014 112, looks like a standard relay,
but it has a diode installed internally in series with the
coil. This difference is clearly indicated on the little
schematic embossed in the side. They also paint a colored
diagonal stripe across the top to indicate it is
unusual.
Ironically, in this case making a special relay was
totally unwarranted; a normal relay can be used by simply
adding a suitable diode (such as Radio Shack catalog number
276-1661) in the wiring to the coil.
FEEDBACK MONITOR RELAY: On the Digital P EFI
system diagram for the North American "Emission A" spec,
item #355 is the "feedback monitor relay". This relay is
mounted under the black plastic cover at the right rear
corner of the engine compartment, alongside the starter
relay and the cold start relay. The cold start relay is a
standard relay, but the feedback monitor relay is anything
but -- don't mix them up. The feedback monitor relay, Bosch
#0 332 014 411, has a diode mounted
internally in parallel with the coil. Beyond this
difference, however, is the fact that the connections on the
base are rearranged, with one of the coil terminals and one
of the contact terminals being reversed compared to standard
relays. The schematic embossed in the side shows the
component clearly, and there is a diagonal paint stripe
across the top to indicate it is unusual.
The feedback monitor relay is illustrated in the
schematics as a normal relay. It's not known if some earlier
cars use a standard relay here.
There was no real need for a special relay here; a normal
relay with an external diode (such as Radio Shack catalog
number 276-1661) would work fine. If you choose to
substitute, however, be sure to rearrange the terminals in
the socket to the standard relay positions.
Editor's Note: As a professional Mechanical Engineer, I
have to express an opinion here: the guy who decided it was
a good idea to make several totally different and
non-interchangeable components all fit in the same socket
should be stood up against a wall and shot. There is simply
no excuse for this level of incompetence.
LATE MODEL RELAY PROBLEMS: Michael Neal warns: "I
just wanted to advise the list of a known problem with late
model Jags, roughly '93 and later. They have several Hella
brand relays in various places for different components.
Underhood usage of them seems to be the worst problem. The
XJ-S and XJ6 use them extensively on everything from A/C
clutch control to EFI main relays. Hella apparently came out
with a replacement to "fix" the failures. They haven't been
working. Whenever I have a strange problem come in, 90% of
the time it's been one of these damn relays. Unfortunately
I'm forced to replace them with what Jaguar provides so
that's what they get. The relays are developing bad contacts
and overheat, failure is usually intermittent. Most of these
relays have a light blue case. You can troubleshoot them by
pulling the relay and jumping between the 30 and 87
terminals."
Leonard L. Peake adds, "There is a Jaguar "Service
Bulletin" in regards to all relays on 1993 cars that have a
date code before "183" stamped on the side."
STARTER RELAY: Dick Broxon of Cincinnati reports
that his '88 XJ-S would fail to start on damp mornings. It
wouldn't even turn over, it would just click. It would start
later, though, when things had warmed up and dried out. He
removed the plastic cover from the relays under the hood on
the right fender and sprayed them with a product called WIRE
DRYER by Snap. He has not had a problem since.
The starter relay, of course, is under the cover
mentioned. It carries more current than most relays, and a
little moisture or corrosion is likely to cause the starter
solenoid to fail to move.
Starter
STARTER: Greg Meboe and Michael Neal report that
Jaguar provided a new design starter beginning in 1988 that
features a gear reduction drive. This starter will fit
earlier V12's, and is smaller, lighter, more reliable, and
just all-around better.
STARTER REMOVAL: Both the Repair Operation Manual
and the Haynes manual list several steps involving the
steering column. This must reflect RHD cars; you don't have
to mess with the steering column at all in a LHD car.
David Johnson wants everyone to be aware that the upper
bolt holding the starter in has a 12-point head, and
therefore requires a 7/16" 12-point socket. The manuals
simply say to remove the bolts. "You can't really see the
bolt head even with a mirror. So because most bolt heads are
6 point, I tried for what seemed like days with several
different size sockets."
"Also I learned not to remove the transmission dip
stick and tube. What a mess! I guess with the car up on
ramps the fluid ends up being significantly higher than the
bottom of the tube."
STARTER SLOW TURNING: Mike Morrin: "Check that the
engine grounding cable (underneath on the left hand side) is
not loose or damaged. This is not particularly an XJ-S
fault, but it was loose on mine, and I would have been
really mad if I had pulled the starter before discovering
it."
The fact is that lots of electrical gremlins have been
traced to faulty grounds, a lot of them to this strap in
particular. As a preventative measure, it might be a good
idea to simply buy another engine ground strap and add it to
the car, connecting it to anyplace on the engine and
anyplace on the chassis.
Alternator
ALTERNATOR: The experts advise that if there is
any indication that your alternator is having trouble (not
charging, low voltage, etc.) that you have it attended to
immediately. If caught soon enough, it can be repaired or
rebuilt. If left alone, it self-destructs and a new one is
required.
Reportedly, one indication your alternator has had it is
that the alternator warning light stays on after the engine
is shut off.
One bit of good news: If the alternator seems to be
charging intermittently (fully charging one minute,
discharging the next as indicated by the voltage gauge) or
has simply stopped charging but has no shorts or burnt
wiring, it might be fixable by replacing just the regulator
itself. This is much cheaper than replacing the whole
alternator, and is easy to do by removing the plastic cover
from the back of the alternator.
A replacement Lucas or Bosch alternator is quite
expensive, but a bolt-in substitute apparently does not
exist; the mount scheme is different than GM alternators, a
Chrysler alternator won't come close to fitting in the
space, and several Japanese units will bolt up but the belt
will be misaligned. Of course, another possibility involves
making an entirely new mount to fit whatever alternator is
available. Any 12-volt internal-regulator alternator of
comparable or greater amperage would serve if it could be
mounted. However, the mount on the engine is rather
convoluted and is involved in mounting the air pump as well,
so it is no easy task to fashion a replacement. Note that
the cost of a new Lucas alternator would pay for a GM
alternator and a very expensive custom-made bracket, and the
next replacement would be cheap.
John's Cars offers a bracket to fit a GM Delco
alternator, complete with a suitable wiring connector.
Michael Minglin says, "A little pricey, but well-designed
and went in without any problems. Now have 100 amp 12SI
alternator for less than $200 total." Minglin opted for a
beefed-up Delco alternator; "The main modification was heavy
duty heat sinks because of the high underhood
temperatures."
If removal of the air injection system is a viable
possibility, you might consider the procedure
described in the section on Engine Modifications.
Also note that there are reports of Motorola alternators
that fit this car, and possibly even fitted from the
factory. Bob Johnson says the number is A5000/12.
Beginning with engine #8S57572, the series of Lucas
alternators was replaced with a Bosch 115-amp unit.
According to the Special Interest Car Parts catalog, the
alternator mount bracket EAC4181 was replaced with EAC9320
at the same time. Perhaps the purchase of this bracket will
permit the upgrade of the earlier cars to the Bosch unit.
Since they all use internal regulators, the wiring
connections should be fairly straightforward.
Also, the 115-amp alternator is driven by a flat
multi-groove belt instead of the V-belt found on earlier
cars. Since the alternator is driven from the crank damper
itself rather than from the pulley that bolts onto it, this
change involved the replacement of the earlier crank damper
C36013 with one with the multi-groove layout, EAC9248
(replaced sometime thereafter with EAC9693 to fit a timing
disk for the Marelli ignition). The pulley part number
doesn't change. So, if you retrofit the 115-amp alternator
to the earlier car, you can either purchase and install a
new crank damper, or you can simply replace the pulley on
the 115-amp alternator with a V-belt type. Note that there
may actually be some problem with this latter scheme;
historically, alternators driven by a single V-belt never
exceeded 60-70 amps or so, larger alternators used two
V-belts prior to the introduction of the multi-groove
belt.
Scott Horner of New Zealand retrofitted the Bosch
alternator to his UK-spec pre-H.E. XJ-S; note that this car
never had an air pump, so the alternator mounting may be
considerably different than US-spec cars. "The Bosch
alternator is bigger than the Lucas and Motorola in most
dimensions. This meant having to drill out the original
mounting bracket ëswing' (technical term!) hole,
definitely needs to be done using a drill press. Trying to
find a replacement pivot bolt with a larger diameter was
entertaining; I eventually got a suitable bolt from a
motorcycle store (but that could just be good old NZ and the
complete lack of parts).
"The unit I got had a grooved belt pulley originally
(although the Jaguar parts manual lists both grooved and
V-belt) so I had to remove this and fit a normal V-belt
pulley. The shaft size on the Bosch is larger than the Lucas
and Motorola, so you can't use the original. I was lucky
enough to be able to rummage through a collection of dead
Bosch alternators, which all have the same shaft size, and
found a suitable replacement, even down to the offset (so
the belt lined up with the crank pulley).
"I was able to re-use the original power connectors on
the back of the alternator (although I had to drill these
out as well to make them fit)."
Regarding the whole general idea of replacing one
alternator with another, John Napoli offers some wisdom: "It
is a good idea, IMHO, to go with a common alternator for
your geography. Volts are volts, what you want is
dependability and maintainability. A large Lucas
infrastructure exists in Britain. In the US, a large
infrastructure exists for GM stuff. The same can probably be
said for other marques, but I have GM experience, and there
is no shortage of ridiculously cheap GM components in the
States!"
ALTERNATOR EXCITATION: The field on the XJ-S
alternator is excited through the warning light, so if this
light is burnt out or disconnected charging may be
intermittent. According to Randy Wilson, "A common enough
design. Lots of alternators will respond like this... some
would never charge. Here's what happens: the alternator
needs a signal to indicate the key is on, and a power source
to boost itself into a charging condition... bootstrapping,
if you will. This power requirement is low enough that a lot
of alternators use the power flow through the charge
light for this purpose. This is called the exciter. And, in
reality, key on is not really an important condition to the
alternator. You just don't want to be driving the exciter
full time, lest your battery will go flat overnight. Once
the alternator is charging, it becomes self-exciting, and no
longer needs or uses this external power source
(oversimplification). Thus the light goes out.
"The exciter is used to induce enough of an
electromagnetic field to start the current generation.
However, there is always some residual magnetism floating
around in a used alternator. With this residual, the
alternator can generate a little bit of current, if you spin
them fast enough. In the case of Lucas (and others) the
current needed to self-excite is fairly low -- low enough
that the current from the residual magnetism can meet the
demand. This usually happens at 2500-3000 engine rpm. And as
soon as the alternator is up and charging, operation is as
normal. You don't have an outside exciter source, but you
don't need it any more.
"The moral of all this is that silly charge system idiot
light is a double-sided test. Everyone knows it is bad when
the light is on with the engine running. Few people know
that it is equally bad if the light stays off with
the engine not running, but the key is on."
ALTERNATOR TROUBLESHOOTING: Michael Minglin says,
"I really like the factory manual's instructions for
checking maximum amps output. Even If I could reach down
there to remove the plastic cover, I could not see to
connect a jumper between "F' and "-". My solution was to
remove the alternator and attach wires from "F" and "-" and
run them out of the back of the alternator, up the inside of
the fenderwell, with a male and female connector on the end
by the cross brace. Now to jump the regulator all I have to
do is connect the connectors. I'm not sure it is worth
pulling the alternator just to make these connections, but I
will never put in another alternator without this
modification."
ALTERNATOR LOAD DUMP MODULE: Reportedly, the
115-amp alternators fitted to the late 80's XJ-S will not
begin to charge until the engine has been revved up.
Although not really a problem, it is somewhat irritating to
see the charge light on when everything else seems OK.
According to Michael Neal: "Actually, there is a fix for
this. There is a device called an alternator load dump
module that was fitted to the later XJ40's and XJ-S's with
the high output alternator. Fitting the module will fix the
problem. The load dump module will cause the alternator
output to function properly at idle without having to raise
the idle speed." The part number for the 115-Amp dump module
is DBC 5896.
Battery
BATTERY: When your battery needs replacing, you
will find that the XJ-S uses an unusual battery -- and that
Jaguar wants $$$$ for it. The Jaguar battery comes with an
enclosed vent connected to a tube to route the vent out
through the floor of the trunk. Batteries are normally in
engine compartments which are well ventilated, and things
still corrode right around the battery. A trunk is not
ventilated at all, so the battery vapors will corrode the
whole trunk. Harry Trafford reports: "the DPO let the Jag
dealer in Miami install a new one. The dealer installed a
standard Interstate mega-something and charged him $150 US
for a $59 battery! The thing out-gassed into the boot and
now I have a major rust repair job ahead of me. And
no, the little red plastic Jaguar vent cover does not work.
There are large rusted out areas up in the buttresses and
along the boot area on either side of the lid, including the
area between the rear glass and boot lid. The only thing
keeping out the rain is the paint. Push a finger into any of
those places and you'll be looking at the spare tire. We're
not talking pinholes here."
Worse yet, batteries emit hydrogen gas when charging, so
you run the risk of blowing the trunk lid off your car.
According to Randy Wilson, an Audi 5000 battery (Audi put
the battery in the passenger cabin, so it has similar
venting provisions) will fit with the addition of a half
inch plywood shim.
Wilson also reports that Interstate offers an add-on vent
kit for their batteries. And there are some marine batteries
with vent provisions.
Charlotte Hand reports that the make of batteries sold at
Pep Boys, Pro Start, offers a "group size 34" battery for
the XJ-S, complete with the proper vent provisions. There
are apparently at least two to choose from, the cheapie and
the high end.
Robbin Lewis says, "Sears now sells an "International"
DieHard Battery that is an almost exact match to the
original Jaguar battery, but at a much cheaper price. The
only thing I had to do was move the 90 deg. fitting from the
right side to the left... easy to do. Just swap the blank
plug on the left side with the angle fitting on the
right."
Delco Freedom batteries, as well as some Champion
batteries, come with a flat top vent/cap assembly that has a
vent opening on each end. Each is sort of a flat oval shape,
but it is possible to connect tubing to them. Hopefully this
is a trend among battery manufacturers; being able to
remotely vent batteries is a plus, and it can't cost them
much to provide the capability. Other Champion designs --
many of which are alongside on the same shelf, sometimes
sharing the same part number -- have obscure venting,
apparently coming out of whereever around the vent caps, and
clearly impossible to properly seal.
A flat-top Champion model 78-2 fits the '83 XJ-S
perfectly. It is a simple matter to fashion a
suitable vent scheme with some 1/4" ID clear vinyl tubing
and a plastic tee. This battery comes with an 84-month
warranty, 24 month free replacement, 36 months free
jumpstart, and is rated at 950 cranking amps at 32ƒF and 770
cold cranking amps at 0ƒF.
The catch? Model 78-2 is a side-terminal battery! The
original top-terminal cable ends must be cut off and
side-terminal cable connectors installed. They cost only a
coupla bucks, the cost is no big deal. In truth, the XJ-S
looks like it was designed for side terminals; there is
precious little room for top terminals, requiring an
unusually short battery height-wise. There's plenty of room
on the front, however, and use of side terminals allows this
full-size battery to fit under that plastic cover.
A more traditional design battery can be made to serve,
but you must find a way to vent the fumes outside of the
trunk. Find or make a cover to completely enclose the vents
on the top of the battery (being selective when you buy the
battery may help here), or an airtight container for the
entire battery. Connect a vent tube and run it out through
the floor of the trunk. B. J. Kroppe suggests "install a DIN
cover over your battery. (DIN battery covers are found on
BMWs and Mercs)."
With careful selection, the vent cover from the old
Jaguar battery can be used on a generic replacement battery.
Georges Krcmery says: "The EXIDE Mega-Cell # E42 50W has a
rectangular slot around its filler caps which exactly
matches the vent cover with only a slight adjustment: I had
to cut off about 1 cm of the slot's lip to accommodate a
similar widening under the nipple of the vent cover. It then
snapped right into place. The battery is about 1/4" too wide
to fit in the tray. Fortunately, the bottom of the battery
has extra plastic on each side and it is possible to
carefully saw off 1/8" on both sides to make it fit."
Michael Neal recommends a battery made by Optima. This is
a lead-acid unit but uses six separate coils instead of
plates; it uses a gel electrolyte and is sealed, no vent
required. "So far they have proven nearly indestructible."
It is about twice as expensive as normal batteries and comes
with a 6-year warranty, free replacement within the first
two years. Neal claims this battery will really last twice
as long as normal batteries, so the actual cost of usage is
comparable. "There is only one basic size, top post or combo
post. Top will work fine..."
William Noorloos adds his experience with installing this
battery: "...when I walked towards the trunk with the Optima
in my hands it jumped the remaining 3 feet all by itself
into position, and just sat there waiting to be connected!
It's a total fit. 100% No fiddling. As a bonus the original
Jag venting thing (Non-metallic British part and
Lucas, but it has not broken yet) fits 100% over the
Optima's 2 emergency pressure relief valves. So in the event
of an alternator thinking it has to drive standard household
appliances, and thereby blowing the battery, the (probably
messy) inside of your expensive Optima will not end up in
your trunk."
Whatever battery you use, you will want to reinstall the
plastic cover over it. If you can make use of the original
battery hold-down bracket, it may make life easier. With the
Champion 78-2 described above, it would fit except that it
blocks off the vents, and the tangs protruding downward on
either end of the battery interfere with a built-in handle
on the battery. Easy enough to cut the tangs off. The vents
require a little more care, however; cutting enough of the
bracket to clear the vents might render it two pieces!
However, with judicious cutting, the top edge of the bracket
can be notched all the way around the corner and part way
down the side, leaving a portion of the side intact. If the
height comes out too low it'd be a simple matter to put
something under the battery to space the battery and
bracket up enough to hold the plastic cover properly.
Alternative plan B is to forget the stock bracket and
simply fashion a bar across the top of the battery. Longer
J-bolts can be used, and two 1/4" holes made in the top of
the original plastic cover. Then, after the battery is
secured with nuts and washers, the cover can be installed
and additional nuts -- real pretty cap nuts or threaded
knobs, they show within the boot -- can be used to secure
the plastic cover.
FYI: the battery compartment in the '83 XJ-S is 10 inches
by 6-3/4 inches. The ideal battery height must be shorter
than 8 inches, terminals included. The height to the flat
top of the Champion 78-2 is 7 inches, and it fits with room
to spare. It is highly recommended that you confirm
the size of the compartment in your own car before shopping
for a battery; the various documentation on what size
battery to use, including those cute computerized battery
selector displays, seem to be wrong more often than they're
right.
One general observation about car batteries and
warranties: There are some excellent $60 batteries out there
with 60-month warranties (or longer). However, some
$60/60-month batteries are actually a scheme to sell you a
$40 battery of the same make every 3 or 4 years. If you buy
a 60-month battery and it dies without due cause in far less
time, you might be well advised to simply write off that
warranty and buy another make -- unless, of course, you
don't mind having to replace your battery every 3 or 4
years.
There are some people who select batteries on the basis
of cranking amps. The logic works like this: The car only
requires a certain number of cranking amps to start, and
almost any battery will start the car when new. However, as
the battery ages, its cranking capacity diminishes with
time, until eventually the battery will no longer start the
car. The more cranking amps the battery has to begin with,
the more it can deteriorate before replacement is required.
This theory assumes a lot, including that different
batteries deteriorate at comparable rates and that the
battery doesn't suffer other types of failure such as
internal shorts. As such, this theory probably doesn't apply
to unusual batteries such as the Optima, but may be a fairly
valid method of comparing conventional batteries.
But to this theory must be added another monkey wrench:
In order to maximize cranking amps, the plates within
batteries must maximize surface area, which is done by
making them look like grids or screens rather than plates.
With successive charges and discharges, these grids get more
and more deformed (metal is etched away when discharging,
plated back on when recharging, possibly in a different
place than it was before), possibly reducing the cranking
capacity faster than flat plates would. Also, the grids
might fracture more easily with vibrations, causing internal
shorts.
DEAD BATTERY PROBLEMS: If your battery is dead
after the car sits for a few days, it's time to check for
current flow when everything is supposed to be shut off.
Craig Waterman says, "On Monday mornings the battery would
be flat. When I replaced the bulbs in the boot lights I did
not think to check that the switch was closing and with a
washer under each screw it is now turning off. So if your
battery is going flat check that boot light switch." Of
course, you normally have the trunk lid open when checking
battery drain current and therefore have to have the boot
lights disconnected by other means, so this particular
possibility may be easily overlooked.
AVOIDING A DEAD BATTERY: Scott Jarvis suggests:
"You can order a Battery Buddy from Outer Banks, (800)
682-2225, part # batbud. It mounts to the side of your
battery and monitors the voltage. When the voltage drops
below a set level, it automatically switches off to preserve
the battery. You just reset a breaker and away you go! Many
of the Boating catalogs should carry this and you may find a
better price."
Kyle Chatman responds: "You can also try Priority Start
from BLI International, Dept HR12, 17939 Chatsworth St.,
Ste. 521, Granada Hills, CA 91344, 800-780-8276. It monitors
voltage drain when the switch is off and disconnects the
battery if it gets too low."
Ned Blagojevic counters: "This is available in a kit form
from Jaycar Electronics (Sydney), kit number KA-1739. The
kit was published in Electronics Australia (Jan 92 issue).
It connects to the accessory line and measures line voltage.
If voltage drops to preselect limit between 10.9 and 11.9 it
shuts off the flow. The kit includes a relay and specs."
John Setters provides a different alternative: "Here in
NZ an enterprising company called PowerBeat has been formed
to manufacture the answer to starting problems. They have
developed an automotive battery which I believe is in two
portions - one section runs the general electrics, the other
is reserved exclusively for engine starting. The URL for
PowerBeat is http://www.powerbeat.co.nz."
Sears also sells a battery with a switch on it, so you
can switch to a "reserve" and get started.
ELECTRIC MOTOR LUBRICATION: Stefan Schulz and
Chuck Johnson Jr. forwarded this procedure, originally from
Chuck Johnson Sr., for oiling a "permanently lubricated"
electric motor: "It is possible to lubricate a "permanently"
lubricated bearing by oiling the wicking that surrounds the
bearing. To do so take a sharp awl (punch) and with a hammer
punch a hole into the ëbell' shaped cover over the
bearing housing. Do this through the vent holes in the motor
and not in the end of the motor itself. The wicking
is housed on the inside of the motor in a ëbell' shaped
tin cover so it is easy to poke a hole in it. Then just take
an oil can (I use a PLEWS oiler so I can get some volume in
there but almost any oil can that can put some pressure on
the oil will work), and ëflood' the wicking. This way
you do not have to take the motor apart to get the bearing
soaking in oil. After this you can periodically lubricate
the bearing by just re-flooding the wick through the hole
you have made. This technique works with all motor types,
auto as well as small appliance and large appliance
motors."
The bearing cover that you are punching a hole in is very
thin metal, much thinner than the housing of the motor
itself. If you punch near the center, you may hit the
bearing itself, and possibly damage or misalign it. Punch
the hole near the outer edge of the cover; there will be
nothing under there except the felt that's supposed to hold
oil.
Of course, some motors don't have suitable vent openings,
so you may have to open the motor anyway. This method still
applies, though, since the bearing inside is almost always
retained by a permanently-attached cover of this sort and
oiling is almost impossible without punching a
hole.
Another favorite item for applying the oil is a
hypodermic syringe, preferably one with a fat needle. With a
little luck, you can buy one in your area without being
arrested for drug abuse.
Now that you have a procedure, you can oil motors
periodically or you can wait until they seize up. Your
choice. Do you really believe "permanently lubricated" means
forever?
In the specific case of the XJ-S electric radiator fan
motor, Schulz adds "the motor is of the "definitely no user
serviceable parts inside, so do not open me" variety. Then
again, you can open the thing by forcing the pry slots at
the top and close it again be replacing the cover and
punching down a bit more metal from the side. Look at one
and you'll see what I mean." Of course, bending the metal
back and forth regularly might result in needing a new motor
sooner than not oiling it at all. In these cases, you might
try a different idea: drill a hole through the housing
itself, aiming for the same area adjacent to a bearing, and
apply oil without disassembly. If it is important to keep
water or dirt out of the motor, cover the hole with a piece
of aluminum tape when you're done.
OIL PRESSURE SENDING UNIT: Many people confuse the
two separate items on the XJ-S, both located at the top rear
center of the engine, just below and behind the bellcrank.
The smaller item is the warning light sender, and is a
relatively cheap item. The larger part is the sender for the
gauge, and it is more expensive and less likely to be
available at a generic auto parts store.
The sending unit is a simple variable resistor. Jim
Isbell says "I have opened up one from a series 3 XJ6 and
found a mechanical diaphragm to wirewound pot contraption.
It essentially acts as a variable resistor that shows high
resistance at low pressure and low resistance at high
pressure."
The gauge itself is actually a current-measuring device
wherein the current heats a wire which expands to move the
needle. In fact, all the gauges except the voltmeter are
essentially the same. Because of the heating required to
operate, such gauges always move slowly and calmly rather
than zipping up and down and making drivers nervous.
Mike Cogswell reports that earlier Jaguar senders were
different than the later -- and they shouldn't be mixed.
"Turns out that the S2 E-Types (and probably XJ-6s of the
same vintage) used 80 psi gauges while the V12s used 100 psi
gauges. The gauges are identical except for the markings,
but the senders are different since they are the same
resistance at different pressures."
OIL PRESSURE GAUGE: Val Danilov reports, "Once I
was sure that the oil gauge was faulty and not the sending
unit, I pulled the gauge out of its housing by removing 3
screws from the back of the plate the gauge was attached to,
as well as 2 metal clips. It's pretty much self-explanatory
once you get to it. Once the gauge was out, in good
lighting, you can see several hair-thin metal wires that run
from the winding to 3 metal posts on the periphery of the
gauge. The wires are soldered to the posts in such a way
that they appear to be misplaced (as if they should extend
farther to some other point), when in fact they are simply
so small that you cannot easily see the points of
attachment. When trying to move them with a tiny
screwdriver, I found one wire which was loose. I used a
regular soldering iron to affix the wire back on the post.
Voila! Problem solved.
"When the gauge is out of the instrument cluster, it is
very easy to test it with a 12 volt supply by simply
connecting one of the electrodes to +, while grounding the
other electrode. Note: the gauge has 3 electrodes (nuts on
the threaded ends of the posts), do not use the middle post.
The post nearest the bottom of the gauge is ground."
85 MPH SPEEDOMETER: Regarding why some XJ-S's came
with 85 mph speedometers, Randy K. Wilson says, "It affected
80, 81 and 82. It may also have been in during 83... not
sure." This author's '83 has a normal speedometer -- but
perhaps it was retrofitted.
David Berman adds, "It resulted from a regulation from
the US National Highway Transportation Safety Administration
(NHTSA) during the leadership of "safety-czar" Joan
Claybrook, during the regulation-happy Carter
administration. The purpose was to prevent kids from being
enticed by the "century" mark. It was effective for the 1980
model year.
"The regulation was thankfully scrapped in 1983 as part
of a regulation-reduction program of the first Reagan
administration. Most non-US vehicles returned to "real"
speedometers for the 1984 model year, but US manufacturers
retained the 85 mph speedos, at least for their high-volume
car lines, for a very long time."
If you don't like the 85 mph speedometer, it can simply
be replaced with a normal speedometer from a different year.
John Napoli says, "I did this on my car about a year ago.
Bought a 160 mph unit from a junkyard. Installed easily and
works great." Of course, the replacement speedometer will
likely have a different odometer reading, and you'll just
have to deal with it.
Electric
Windows
ELECTRIC WINDOWS: There are reportedly three
different types of window motor used in the XJ-S coupe: A
Delco unit up to 1987, a different Delco unit 1988-89, and a
Bosch from 1990 on. The early Delco motor has a large
cylindrical housing, while the 1988-89 Delco unit has a
smaller, more rectangular housing -- perhaps better
described as a cylinder with two flat sides.
The convertibles, of course, have another motor operating
the rear windows, and apparently have different units in the
doors as well.
Unfortunately, problems are reported with all types, even
though none of them are Lucas. Some of the problems
discussed below apply to all, and some apply only to
particular units as noted.
ELECTRIC WINDOWS -- KEYLESS
OPERATION: Some of us prefer
the electric windows to be operable whenever we're in the
car, not just when the ignition is on. If you share this
preference, there is a "window lift relay" under the
passenger's side of the dashboard that provides power to the
windows whenever the ignition is on. All you have to do is
remove this relay and connect the power wire directly to the
wire to the windows, and the windows will operate whenever
the buttons are pressed. Since the buttons are inside the
car anyway, it's not exactly a security risk.
SLOW-MOVING WINDOWS: The early Delco windows
always move slowly. This tip is from Leonard Berk: His
windows operated very slowly, so he sprayed WD-40 down the
frames without even dismantling the doors. The windows
operate like new. Perhaps WD-40 isn't the ideal substance
since the odor may be objectionable to some people, but it
is worth noting that lubrication may be in order. Victor
Naumann says, "Try not to use oil in the channel, it
destroys the rubber. Silicone spray or graphite works OK.
WD-40 is a great lube, but not for rubber, it makes it
swell. Jag makes a very expensive lube called Glietmo, but I
prefer silicone."
Paul Bachman says, "In my experience, lubricating rubber
window guides is only a short term solution and seems to
aggravate the sticking in the long run (gets gummy as it
enevitably dries out). I have had very good success
lubricating the guide rails on electric windows (including
my 85 XJ-S) with graphite. It is difficult and a little
messy to get it rubbed into the right places, but once in
place it works for a long, long time."
On the author's car, one reason for slow windows was that
the little roller that slides in the track at the bottom of
the glass had gotten all screwed up -- see below.
John Himes talks "...about possible fixes to the drivers
window not going all the way up without using their hand. On
my 88 XJ-S, the problems was that one of the screws was
removed by a PO, or had fallen out over time that mounts the
window motor to the door & the others had become loose.
The motor assy. would move when you raised or lowered the
window. After tightening the screws & new lock washers
(with the window all the way up so it would fit correctly),
the window now goes all the way up & I no longer have
the fingerprints on the window (inside anyway)."
John Setters reports: "Two problems caused my drivers
side window not to close fully without assistance:
- Window motor mounting had come loose.
- The lift assist coil spring was binding on
itself.
"Firstly remove the door trim panel - the hardest part! I
found that I needed to close the window fully before
tightening the motor mounting bolts. This is the way to
assure correct positioning of the closed window. Do this by
applying upward lift with your hand under the slide rail at
the lower edge of the glass. Then tighten the bolts.
"Complete lift was hampered by lack of spring tension.
Although well lubricated by grease too much friction
existed. I applied spray CRC to the spring then operated the
up and down movement to work the CRC into the spring coils.
Heh presto it all works fine now."
John Napoli suggests adjusting the track at the rear of
the window. There are two screws that hold this section of
channel in place; one is under the door panel near the
bottom rear of the door, and the other is clearly visible on
the end of the door above the latch. The track is removable
to facilitate replacing the glass. The bottom screw has a
very large washer on it and fits through a large hole in the
door sheet metal, so the track can be moved around quite a
bit before tightening it down. The upper screw doesn't have
as much room to move, but can still move a little. It is
helpful to loosen both screws at the same time to fully
investigate the range of possibilities.
Napoli also suggests "If you can't find an adjustment
that solves the problem, replace the lining of the rear
channel. Jag sells a replacement channel. I suspect that
good old aftermarket channel felt can be installed in the
old channel assembly." The problem with old channel felt is
that the fur wears off, allowing the glass to rub directly
on the rubber underneath. The friction is hence much higher
than it should be.
If you have the early Delco window motors, once you have
addressed all the possible problems listed above, your
windows will still move slowly. The final solution is to
install a relay control system; see below.
WINDOW/TRACK SEPARATION: John Napoli says: "I once
had a weird window failure in my car. The PO had replaced
the rear window channel on the drivers side. One day I
lowered the window and thunk -- the window drops down
out of sight. Opened the door up and found that the metal
channel that the glass rides in had been pulled away from
the glass. It was as if the glass had a positive stop on the
way down. The motor kept on pulling the glass down after it
hit the stop and pulled the arm off. Put it back together
and it soon happened again. I solved the problem by taking
the glass out, supergluing the arm to the glass (in the
correct location!) and installing a sophisticated support
that the steel arm would hit when the window was lowered. It
was a carefully shaped chunk of 2x4. You need to glue the
channel to the glass in addition to adding the stop because
if the channel is loose on the glass it will eventually
slide sideways and prevent the window from opening or
closing properly. The glue locks the channel in position and
the stop prevents the window from dropping too far and
allowing the motor to pull the channel away from the
glass.
ELECTRIC WINDOW REGULATOR DRIVE ROLLER PROBLEMS:
The little roller on the end of the motor arm on one window
in the author's '83 XJ-S was FUBAR. Basically, the shaft the
roller turns on is attached to the arm like a rivet, and
this attachment worked loose, allowing the roller to cock
sideways and jam in the track on the window. As the motor
forced it back and forth in the track, the edges of the
sheet metal track chewed the plastic roller all to bits. No,
you can't buy a new roller from Jaguar -- they want you to
buy the entire window regulator mechanism. The ë83
clearly has the early Delco regulator, but all of the
regulators have rollers of some type and may occasionally
have similar problems.
For anyone with a lathe and some plastic stock, it would
be a simple matter to make a new roller. Unfortunately, I
don't have either. I went to a building supply store and
looked through their collection of rollers intended for
sliding closet doors, drawers, shower doors, etc. I
immediately noted two concerns: 1) the roller in the Jag
window was smaller than any of these; and 2) the roller in
the Jag window has a sort of offset -- the bearing surface
isn't in the center of the roller, but over to one side. In
the Jag, the pin is shaped like the head of a flush head
bolt, so that no part of the pin extends beyond the roller
and jams into the track. Only a select few of the rollers in
the building supply store had a similar feature.
I selected a package of "Closet Door Hardware" described
as "No. 8544, 7/16" Offset Hanger Pr." and made by Door
Products Inc.; I'm sure there are generic equivalents in
just about any such store. This package contains two hangers
intended for the top of a hanging, sliding closet door, each
with a little roller to fit into a track. The 7/16" refers
to how much the offset is, no importance here. In fact, the
entire hanger is forfeit except for the roller itself. There
are probably several other types of hangers, with various
offsets, all using the same or similar roller. It is
necessary to grind off a rivet flare to remove the roller
from the hanger.
The roller acquired is the smallest I found, but still
too large; it is about 20mm in diameter, while the Jaguar
window roller is about 17mm. However, it was a simple matter
to mount the new roller onto a 1/4" bolt, chuck it up in a
drill, and grind off the outside edge until it was the
correct diameter. This roller, along with the Jaguar
original, is illustrated in
Figure
15.
This roller also had the offset bearing, although it was
not as long as the Jag original. When assembling, it was
necessary to add a few washers behind it to space it out the
same distance from the arm as the original had been. I made
washers out of plastic so they wouldn't jingle. I also made
sure their OD was small enough to not interfere with the
window track.
I also was able to find a shoulder bolt, or "axle" bolt,
that I was able to modify for use. It was an Allen socket
head bolt with a 1/4" diameter shoulder 3/8" long, and a
10-24 threaded end beyond that. If I had intended to use
this bolt to hold the original Jaguar roller, I would have
had to grind a taper on the bottom side of the head to match
the tapered surface within the roller and allow the head to
recess far enough into the roller so as not to protrude at
all.
For this new roller, however, the problem was different.
The new roller has a recessed opening for the head of the
original pin that held it, but it's flat-bottomed, not
tapered. There is therefore no reason to grind on the bottom
side of the head, but the top side protrudes entirely too
far -- this head is much taller than the recess is deep. So
I had to grind about half of the height of the head off.
This removed the entire Allen socket, leaving me no way to
tighten it. So I cut a straight slot across the top for use
with a screwdriver.
When assembling, I put the roller and the homemade
plastic washers on this shoulder bolt, screwed on a nut,
inserted it through the hole in the arm, and put another nut
on the back side to hold it. When tightened up, this
positioned the roller about the same distance from the
surface of the arm that the original had been.
I chose not to install this roller in the original hole
in the regulator arm. Instead, I drilled a new hole 1"
closer to the motor itself, making the arm effectively 1"
shorter, in hopes of improving the leverage the motor has
moving the window. This worked perfectly, but since the arm
is 15" long to begin with, this provides only a small
percentage improvement in leverage. Still, it's easy to do,
and every little bit helps.
Of course, the window motor and regulator assembly is an
AC Delco; perhaps you can figure out what other cars it was
used in and find a cheap replacement in the local
junkyard.
ELECTRIC WINDOW SWITCH PROBLEMS: Reports of
problems are more common with earlier Delco units. That may
be partially because the cars are older, but the early Delco
system definitely suffers from overloaded switches. The
switches are inadequate for the current involved and the
contacts get burned. Even though the later Delco and Bosch
motors are physically smaller, they still move the windows
at a good clip and probably draw a comparable amount of
current; we'll probably hear more about switch problems in
later cars as the years go by.
Bob Colson of the Jaguar Club of Southern Arizona points
out that the window lift switches can be taken apart. First,
remove them from the panel -- easiest to do by first
removing the panel so you can push them out from behind.
Then, by spreading the housing slightly, the rocker itself
can be popped out. Then the parts can be cleaned up and
repaired as needed. The two rocking contact plates are
symmetrical but only one end of each gets worn, so the
plates can be reversed to extend their life. The cruise
control on/off/resume switch is constructed similarly.
Phil Patton adds: "Usually it seems the plastic things on
the ends of the springs wear unevenly for some reason. When
cleaning the switch replace the one from the left side to
the right and vis-a-vis."
Another solution is to replace the switches with generic
double pole/double throw self-centering rocker switches with
better contact ratings. The difficulty here, obviously, is
getting them to look right. Phil Patton sends this tip: "I
have found a switch which is less expensive, IMHO looks much
better, and I am positive will last much, much longer. This
part fits the existing hole perfectly and has a small,
coloured illuminated strip across it, making it easy to find
in the dark. It is rated at 20 amps @ 12 volts and is
(unlike the Jag switch) completely sealed so that dirt
cannot contaminate the contacts. The part is GC number
35-3565 (green light) or 35-3570 (red light). They should be
available from any decent size electronics parts house. The
only modification necessary to use this part is to cut off
the plug on the wiring harness and replace it with push-on
lugs on each wire. If you don't like the light then just
don't connect it."
Stephen Wood says, "I replaced the power window and power
lock switches in my '76 XJ-S with '82-92 Camaro/Firebird
units, $10 ea. new and they work great. I had to make a
wiring jumper and a sub plate for mounting, but they
function better than the Jag ones ever did."
Perhaps the best solution, and one that maintains the
original appearance, is to install relays to operate the
windows and operate the relays with the stock rocker switch.
See below.
WINDOW CONTROL RELAY INSTALLATION: Both the
dragging window motors and the burned switch contacts are
symptoms of the same problem: There is too much current
going through those switches. The high resistance, due to
marginal or overloaded contacts, results in less than ideal
power to the motor and causes the contacts themselves to
fail often. This author measured the voltage at the window
motor with the window trying to close, and it was less than
8 volts -- and dropping below 7 volts as the motor
struggled. This operating voltage means the motor is only
developing about 45% as much power as it would at 12V.
A set of window control relays will provide full battery
voltage to the window motors, eliminating the losses in the
wiring harnesses and switches. See
Figure
16. Two SPDT relays will be needed for each window,
an "up" relay and a "down" relay, and each will need to have
serious contacts -- at least 10-amp rating. Since the
current needed to operate the relays is minimal, the rocker
switches should last forever -- even if they've already been
abused and cleaned up a couple times.
The XJ-S comes with a relay referred to in the Jaguar
literature as a "window lift relay"; all this relay does is
turn off power to the windows when the ignition is off. I
will continue to use that term when referring to that relay,
and will call the new relays being added in the following
scheme "window control relays." Try not to get confused.
Since window motors are permanent magnet motors, the
direction they run depends on the direction of current flow.
The wiring within the motor itself is not grounded.
To run one direction, the switch grounds one motor lead and
applies 12V to the other. To run the other direction, the
same switch grounds the second lead and applies 12V to the
first. The window control relays should be wired to do the
exact same thing. In the wiring scheme shown, the
normally-closed contacts on the relays ground both leads of
the motor when the relays are idle, and each relay switches
one lead to 12V power when energized.
A massive power wire -- 12 gauge or so -- must be routed
to the window control relays directly from some heavy-duty
source (any big, fat brown wire). You can toss in an inline
fuse for safety, but it's probably a better idea to use the
original thermal circuit breaker; it will do a better job of
protecting the motor from overheating if the power is left
on (somebody sets a book on the switch).
For the passenger's side window, it is quite convenient
to use the existing 12V power source and circuit breaker for
the windows, leaving the breaker mounted right where it is;
just connect a new wire with a 1/4" spade terminal to the
output side of the breaker and route it to the new
relays.
For the driver's side, it may be preferable to just buy a
new circuit breaker and power it from a lead to the fusebox;
this would eliminate the necessity to run a heavy wire from
the existing breaker on the passenger's side across the car
to the driver's side. The original "Otter" circuit breakers
are inordinately expensive and of unknown rating (apparently
big enough to allow both windows to run at once, probably
too big to properly protect a single window motor), but
generic circuit breakers are available in auto parts stores
in 10A, 15A, 20A, 25A and 30A ratings for around $5 each.
The 10A should work for one window motor; if it trips too
often when the motor seems to be operating properly, just
replace it with the next larger breaker. All of these
generic automotive circuit breakers are "thermal" type, as
opposed to the electromechanical circuit breakers typically
used in homes.
For the relays, 12V DPDT relays with 15-amp contacts from
Radio Shack, cat. no. 275-218, will serve nicely. Since SPDT
relays will do the job, wire both contacts together; two
15-amp contacts working together definitely should handle
this job!
The sockets that Radio Shack sells for these relays are
not recommended; buy a handful of 3/16" spade terminals
instead. Radio Shack seems to only offer 3/16" spade
terminals in a box with a lot of other connectors, and since
you need 16 of them you'll be buying a lot of boxes. If you
go to an auto parts store, though, you may be able to buy a
box with the correct "crimp-on" terminals alone. Even if the
terminals come with plastic insulating collars, it is
suggested you rip the plastic collars off and throw them
away, solder the wires to the terminal after crimping, and
insulate them with 3/16" and 1/8" heat-shrink tubing.
Since SPDT relays will work, automotive relays are
another option -- if you can find some with an 87a (NC)
terminal. Most of the relays sold in auto parts stores
(usually for controlling driving lights) have two 87 (NO)
terminals and no NC terminal, which won't work. Suitable
relays include the one used on the XJ-S
electric radiator fan, SRB411, and all of its
substitutes.
Another option would be to use two normal driving light
relays (no NC contacts) instead of each SPDC relay. Rocking
the button should operate both relays, and one should make
the power connection while the other makes the ground. This
wouldn't make any sense if relays were priced the way they
should be, but the fact is that you might find two driving
light relays are cheaper and/or easier to find than
one SPDT relay.
Automotive relays require 1/4" spade terminals, which are
a good deal easier to find than the 3/16" terminals needed
for the Radio Shack relays. Again, insulate them with
heat-shrink tubing, 1/4" and 1/8" this time.
The relays can be located anywhere between the switch and
the motor; simply break into the RG and GR (right side) or
RU and GU (left side) wires from the rocker switch to the
motor and wire in the relays as shown. Within the door
itself is one possible location; in this case, a massive
ground wire should be routed back into the car -- relying on
ground contact through a door hinge is not recommended.
Also, before closing the door up, it'd be a good idea to
fasten the relays down (possibly with foam tape) and tie the
wires down, and run the window up and down and operate all
the latches to make sure the wires aren't in the way of
moving parts.
Another possible location is adjacent to the footwells;
you can intercept the wiring near the door hinge by removing
the kick panel on the side of the footwell just forward of
the door (2 screws). There is a pocket that looks like it
was made for these relays behind the kick panel. There is a
door lock relay in the same space, but it isn't taking up
all the room. The wires from the door all go through this
space, and there are a lot of them -- stereo speaker,
electric mirrors, puddle light, door lock, and window. They
are also plenty long enough, making it a simple matter to
cut into the two window wires and install the relays. This
location makes it unnecessary to have to route heavy 12V and
ground wires into the door, or even to take the door panel
off.
The relays can also go within the console if preferred,
although that reuses a lot of the original wiring to the
motors and reduces the potential benefits of installing
really heavy power wiring.
It doesn't make good electrical sense to use the existing
circuit breaker to protect the wiring to the rocker switches
and new relays, since that's a heavy duty breaker and they
are now a low-power circuit. Instead, provide an in-line
fuse to the rocker switches; a 2A or 3A fuse should be
plenty to power the relays. Physically, this means that the
NU line from the window lift relay to the rocker switches is
disconnected from the relay and connected to a fuse instead.
You can use a generic fuse holder for a professional
installation, or you can simply put 3/16" spade terminals on
the wires and connect them directly to one of those
newfangled plastic fuses.
Remove and discard the window lift relay, it won't be
needed any more; the window control relays themselves will
accomplish its task. Unfortunately, the window lift relay
doesn't have a NC connection, so it cannot be reused as one
of the four window control relays.
Where the power to the other side of the fuse comes from
is a matter of preference. If you wish the system to work
the way it originally did (windows won't move unless the
ignition is on), then connect the WK wire that originally
controlled the window lift relay to the fuse, as shown in
Figure 16. If, on
the other hand, you'd rather the windows worked whenever you
hit a button regardless of ignition, just connect the fuse
to a constant 12V power supply -- and there happens to be
one right nearby, connected to the input side of the circuit
breaker.
A minor complication: One might assume that the window
rocker switches are a center-off, DPDT operation, and the
wiring diagram for the window circuits in the Supplement to
the Jaguar XJ-S Repair Operation Manual is obtuse enough to
let you go on thinking that -- but they are not. Each rocker
switch is actually two individual SPDT switches, neither of
which is center-off; both have NC and NO contacts. With the
rocker in the center position, the NC contacts on both
switches happen to be connected in such a way as to send 12V
to both leads to the motor. Since 12V at both leads results
in no current flow, the motor doesn't move. When you rock
the switch, one of the two internal switches disconnects the
12V source and connects that motor lead to ground, while the
other internal switch doesn't move -- hence, the motor runs.
Figure 16 shows the
switch schematically correctly, although it doesn't really
indicate the actual physical operation properly.
All of this is normally just fine, except that all those
leads are hot all the time. Something to keep in mind while
working in the area, especially if you have bypassed
the window lift relay so the windows are operational at
all times with or without ignition.
With the window control relay installation, however,
these hot leads cause the relays to be energized when the
windows are not moving. Rocking the switch causes one relay
to unenergize, and the system will in fact work just
fine; the relays will just get warm. However, if you have
wired the system so that the windows can be run with or
without ignition (see above), the relay coils would be
draining the battery when the car is parked. Ungood.
The solution is to exchange the 12V and ground
connections to the rocker switch so that both motor leads
are connected to ground when the rocker is centered -- just
like you'd have expected Jaguar to do in the first place.
You can make this change by cutting and splicing wires, but
an easier way is to move the connectors around on the plug
that connects to the bottom of the rocker switch, putting
the NU wires back where the B wires were and vice versa.
With a piece of 3/16" OD brass tubing (available at hobby
shops), it is a simple matter to pop the connectors out of
the plug; just insert the tubing into the round hole around
each connector, and it will compress the tangs on the sides
of the connector itself and allow the connector to be pulled
out the back side. Then they can merely be pushed back into
the proper holes until they snap into place. This change may
even be desirable without installing window control
relays, since the windows will still run exactly the same
way; you just won't have hot leads when working on the car
any more. Note that, for operating window control relays,
the ground wires could merely be removed since they are not
used.
When fiddling with all this wiring, rewiring, relay
installation, etc., etc., trying to keep track of which
circuit will move the window up versus which one will
move the window down will drive you nuts. Instead,
just forget about it. When you're all done and everything is
working fine, if the button must be rocked the wrong way to
move the windows, just turn the connector around on the
bottom of the rocker switch. If you prefer, you can
reassemble the console but leave the rocker switches hanging
out of it by the wires; when you're ready to test it, just
hold one rocker switch in your hand and push it one way or
the other and note which way the window moves. Then turn the
switch whichever way is correct and snap it into the
panel.
This author has installed window control relays in my '83
XJ-S. I can report that the modification is a resounding
success; the windows now zip up and down like they should.
It is now clear to me that this is yet another modification
that should be done by all XJ-S owners ASAP, before
their stock window switches bite the dust from overload.
ELECTRIC WINDOWS -- EARLY CIRCUITRY: According to
the Jag manual, "Selections can be made on one switch at a
time, the driver's switch over-riding the other panel
switch", possibly to avoid overloading the circuit breaker.
However, the supplement shows no such override and both
windows on this author's '83 run at the same time. Randy
Wilson says, "The SII XJ6, and early XJ-S, were set up in
the manner your book describes. The switches are double
pole, triple throw (down, pass-through, up). With this early
system, you could only run one window at a time. And, if a
switch failed such that the pass-through didn't work, all
windows downstream also quit. Since the most used window,
the L/F, is also first in the daisy-chain, it's not uncommon
to see a SII with no working windows. This went away
(all switches wired in parallel) with the SIII. I'm not sure
exactly when the S changed over, but it was certainly by the
time the H.E. was introduced."
If you have an early car and are having trouble with this
system or these switches, the ideal solution might be to
simply install the window control relay scheme described
above and delete that daisy-chain nonsense. If your original
switches can be made to work at all, they can be wired to
operate the relays, and you will no longer be limited to one
window at a time. Since you would be providing new and
substantial power wiring to the window motors, there's no
risk of overloading any existing wiring.
1988-89 ELECTRIC WINDOW MOTOR FAILURES: On the
ë88-89 Delco units, the housing on the motor itself
gets loose and jams the rotor, or lets water in. Victor
Naumann says, "I have replaced a lot of motors that the back
has fallen off of and water has ruined."
Steven Draper reports, "After taking the door apart, I
noticed that the case on top of the window motor that holds
the magnets is held on by only two bolts. The rear bolt had
slipped some, and could not be tightened completely because
of the soft metal. The bit of play between that casing with
the magnets and the internals of the motor that spin about
was enough to cause the motor to only work when you beat the
side of the door. I inserted a slightly larger bolt with a
nut on the bottom. I was able to put the new bolt in without
taking the motor out. Believe it or not, the window now
rockets up and down. If you've got a window that doesn't
want to go up and down and tapping on the door helps, this
could be your problem.
"It was interesting because the case had four bolt holes
but the motor part with all the gears in it only had two
holes for the case to attach to." It might not be a bad idea
to put some aluminum tape over the unused holes to keep
water out.
Peter Cohen provides part numbers: "The January 1987 -
January 1989 parts book lists the non-convertible window
motors as: Left: JLM975, Right: JLM974, and the regulators
as Left: BCC5775 and Right: BCC5774. Convertible is listed
as Motor: Left: JLM1496, Right: JLM1495, with the
convertible regulator listed as Left: BDC5079, Right:
BDC5079.
"The right side Delco motor that I removed had a paper
label with the number 20060098 above the numbers 121 and
30P8 (the left side label was illegible).
"BTW, on the Delco motor, if you put the stator on
reversed from how you took it off, the motor does the
opposite of what the switch intends." Might be a good idea
to mark which way the case goes before disassembly, although
you could conceivably just turn the switch around in the
console.
1988-89 ELECTRIC WINDOW MOTOR SOLUTION: Peter
Cohen reports, "'88's & '89's are known to have problems
with the window motors. I have an '89 XJ-S and have replaced
both window motors with the new style Bosch motors. I highly
recommend them. The windows just zip up and down like they
never did with the Delco motors. If you have an extended
warranty, this should be a no brainer -- make them buy you
the new motors. If the warranty company won't come through,
sue their no good ass in small claims court.
"Some other insights into the window motor upgrade:
"1. When this upgrade first came out, it was only sold as
a complete motor/regulator assembly. It is now available as
two separate parts.
"2. When I bought my left side assembly from SICP a few
years ago (about $325 then), two of the holes on the motor
seemed not to line up with the holes in the black sheet
metal panel in the door, & I had to drill new ones. This
was not a problem with the right side, separate motor &
regulator assembly which I bought in April from SICP on
their close outs, but I did have another problem: Both the
regulator and motor that SICP shipped me as right side were
actually left side. The regulator assembly was in a sealed
Jaguar package with the correct Jaguar part number for the
right side. I took this to the local Jaguar dealer who
cheerfully swapped it for a left side regulator, without my
asking, and without asking where I got it. Being so
successful with the regulator, I took the motor to another
Jag dealer. Now, here's where it gets interesting. The motor
from SIPC came in a Bosch box, so I was a little nervous
about trying to swap it at a dealer. I brought in the motor
without the box, and again, the dealer swapped it without my
asking. However, the number on the motor was different
enough from the one I brought in that it wasn't just the
difference between left and right. Also, the motor from
Jaguar comes with 3 torx screws, and while the Bosch unit
had no external wiring at all (just tabs to connect the
wires), the Jaguar issue not only has the wires, but they
are potted onto the motor. This leads me to believe that
there is a standard issue Bosch motor that we can buy and
adapt, even if Bosch won't sell the Jaguar number.
"3. There is a different type of plug on the Bosch motor
(although still only 2 wire). You can cut & splice your
old wires, or Jaguar sells a clean little adapter assembly
to do it right. I have done it both ways, and both work. The
adapter is $40, so you really have to want it."
"I get the impression that SICP is no longer selling
window motors because of the problems they have had.
"A few weeks ago, I found myself in a Mercedes repair
shop, and noticed a window motor lying on the table. Dang if
it didn't look exactly like the one I put in my XJ-S. Which
leads me to speculate: How many other cars use the same
motor? Audi? BMW? Volvo? Saab? Opel? A wrecking yard Bosch
motor in conjunction with a new Jaguar window regulator may
be just the ticket for replacing those crappy Delco motors
without bleeding from the ears at Jaguar's price."
"The Bosch motor's drive gear has a different number of
teeth, so the regulator gear of the Delco won't mate with
it, thus the need to replace the regulator."
BOSCH ELECTRIC WINDOW GEAR FAILURES: On the
1990-on Bosch units, the gears strip. Matthias Fouquet-Lapar
says, "I almost fall flat on my face when the workshop told
me that the window motor for a '91 XJ-S was more than $800!
They found a way to adapt the older motor type. They told me
that there is some nylon drive gear which easily breaks and
there is no good fix available, so they retrofitted the
older type motor. It seems to require some major rework to
the window mechanism though." Considering all the expense
Peter Cohen went to in upgrading his Delco motors to the
later Bosch (see above), he probably doesn't want to hear
that shops are doing the reverse.
ELECTRIC WINDOWS -- CONVERTIBLE: Larry Barnes
says, "I just got to repair the left rear window
motor on "her" '92 Convertible. I also had this same problem
with the right rear window motor. Dare I say it, "a
design flaw"??? No, couldn't be...
"Seems in the gear box (the flat lid pops off for easy
access) there is a ring gear and a worm gear and a output
linkage linked to the ring gear with a 1/4" flat/round
rubber pad/shock absorber. Well, there are three little
"ears" on the rubber shock absorber that will break off and,
get caught in, and jam up the works (always with the window
in the down position when you are 40 miles from home and
it's pouring down rain). They seem to have no other
practical use!
"The fix is: Remove the FOD, spin around 3 times
anti-clock wise, and reassemble. Everything works great
again..."
ELECTRIC REAR WINDOWS (CONVERTIBLE): Trish Duffy
says, "On the convertible, the two back windows
automatically retract when the hood/top is lowered, and
close when the hood/top is raised. These back window motors
can burn out if the top raise/lower switch is held
"on" for too long."
Larry Barnes says, "My 1992 convertible has a "Delco of
England" window motor for the Rear\Side windows. I tried to
order just the motor, but Jaguar wanted to sell me the whole
shooting match (with regulator) for $360. I found a local
motor shop the would rebuild the motor."
There apparently are other problems with these windows,
though. Andrew Corkan says, "I have a '91 XJ-S convertible
and the rear window, lowered automatically when the hood
(convertible top) is lowered, stopped working. The window
remained up, but otherwise the operation of the hood was not
affected. I tested the usual, relay and fuse, etc...
"Following the Jaguar service manual, 1974-88, vol 4 page
76-11, I removed the rear quarter trim panel. I then removed
the plastic motor cover. It is held in place by both
adhesive and three plastic button fasteners. I missed one
fastener and broke the thin plastic cover. I also unplugged
the two motor wires.
"The failure was in the gearbox on the motor. The gearbox
has a thin metal plate that covers a worm gear on the motor
coupled to a plastic gear that couples to the window
movement linkage. I removed the four bolts that hold the
window linkage to the body. I lowered the window half way by
hand and rotated the linkage to remove it from the recess in
the body. ( I did not remove the rear storage compartment or
the hood lift linkage as stated in the service manual. )
"I don't know why the gearbox failed. The gear box
contains a rubber coupling consisting of 6 pie-wedge shaped
sections that couple a three-pronged part on the plastic
gear with a three pronged part on the metal shaft that runs
out the back of the gear box. These wedges had popped out
and knocked off the gearbox cover. It appears that the
window motor is just run for a fixed amount of time and
there is no switch to stop it, so maybe the rubber parts
were just squeezed out when the motor stalled at the end of
the travel. I saw no limit switches.
"I jammed the rubber back in place and replaced the metal
cover and peened that back into place. When reinstalling the
motor it is important to run the hood up or down so that the
other window is in the halfway position (as per the service
manual). This puts the window linkage in a position that
allows access to all three mounting bolts for the gearbox. I
repacked the gear box with general purpose grease, and added
lithium grease to the linkages.
"It worked fine 6 times (up or down) last weekend. So far
so good.
"The critical and possibly breakable part appears to be
the plastic gear in the gearbox. All other parts are robust
metal or easily cut rubber. If you find these gear boxes,
keep the parts.
"The motor looked generic. If it fails it should not be
too tough to find a substitute, just be sure you save the
worm gear that is on the shaft.
"My time was 3.5 hours, mostly trying to figure out which
screws to remove and how to remove the linkage. Next time it
will take about 1 hour."
ELECTRIC REAR WINDOWS (CONVERTIBLE) -- ACCESS NEXT
TIME: Julian Mullaney says, "I was buggering about with
my XJS Convertible rear windows which wouldn't work properly
(just like everyone else's) and noticed that the panel that
covers the motors is held in by several screws, one of which
is behind the window glass. If the window ever gets stuck in
the up position, or any position except all the way down,
this screw would be utterly inaccessible, i.e. behind the
glass. This means that the interior leather panel could not
be removed and the motors could not be accessed at all. One
would be truly screwed if this were to happen. I think I
will leave these screws out next time. There are enough
other screws holding the panel in place."
Andrew Corkan responds, "It happened to me. I went to my
basement and found a philips screwdriver tip, the kind you
buy in packs of 6 for driving drywall screws with your
electric drill. I then went to my local Service Star store
and bought a strip of steel, 1/2 inch wide and 1/8 inch
thick. I cut the philips part off the driver and drilled a
hole in the strip of metal and brazed in the stub of the
philips screwdriver into the hole. This gave me a right
angle screwdriver, with a bend able handle, that was flat
enough to get into the space. I could rotate the screw 90
degrees at a time and it took 15 minutes to get it out! If
you do this be sure to file all the sharp edges off the
metal; I then wrapped the metal in plastic tape to prevent
damage to the leather. Before I replaced the screw I cut it
off so it will only take two rotations to get out of the
hole. Now that I think about it, maybe I will replace it
with a hex head screw, easier to turn."
Electric
Mirrors
ELECTRIC MIRROR DISASSEMBLY: Sorry to say, the
electric mirrors were never intended to come apart. Here's
how they went together: The plastic rim was put into place,
then the motor assembly was put in over it, and then three
screws were put in through holes in the mirror platform to
hold all that to the housing. Lastly, the glass itself was
mounted on the platform with foam tape -- completely
covering the access holes to the three screws. Your chances
of getting the glass to peel off of the plastic platform
without breaking it are slim. Of course, if the entire
reason you're reading this paragraph is because your glass
is broken and you wanna know how to replace it, that's the
trick -- just bust the glass into lots of little pieces
until you can poke holes in the foam tape to get to the
mounting screws.
If you don't wanna break the glass, you have a bit of a
task ahead. Fortunately, you can easily see just how
difficult it is before you even start. Run the electric
mirror to the full up position, and pry it upwards a little
more with a screwdriver and look under it. You will see two
Phillips head screws. These two are not that difficult to
get to. Run the mirror to full down and look between the top
and the edge of the housing, and you should see the third
Phillips screw dead center. This one's a real pain, since
it's farther away from the edge than the lower two. Trust
me, getting these three screws out and back in is the only
difficulty with removing the motor assembly; if you can
figure out how to do that, the rest is cake. The mounting
lugs on the motor assembly are open slots, so removing the
two bottom screws and just loosening the upper one may
work.
As long as you have the thing out, a couple of
suggestions: First, the plastic rim may have flashing tabs
around the edge of the inner rectangular opening, notably at
the 3 o'clock and 9 o'clock positions. These tabs may
interfere with operation of the mirror, and should be cut
off. In fact, it isn't a bad idea to use a sharp blade to
cut about 1/8" off the right side of this opening, enlarging
the entire rectangle.
Second, the motor assembly mounts with three lugs, but
there is a fourth unused lug that gets in the way during
assembly. You may want to just cut this fourth lug off to
ease reassembly. It does nothing for operation, though, so
you also might just leave it alone.
Third, the bottom center portion of the plastic rim
distorts, so the screws tend to pinch the mounting slots
right on the edge rather than getting a secure grip. My
solution for this was to attach a 1‡" length of popsicle
stick to the bottom center of the housing with a piece of
aluminum tape. This holds the plastic rim up into the proper
position while the bottom two screws are tightened.
Note that the motor assembly itself is also permanently
assembled, by melting tabs. You'll have to grind them off to
get it open, and then contrive some other method to hold it
shut again.
The motor assemblies for the left and right sides are
exactly the same, not mirror images or anything.
ELECTRIC MIRROR ADJUSTMENT SWITCHES: When the
parts man at a Jag dealer was asked about these joystick
switches, he had the part number memorized! We're talking
junk here, and they charge $85 each for the
two of them. Note that for '92 the joysticks were replaced
by a fancy electronic adjustment scheme, and the following
ideas do not apply.
Note: The mirror circuits are always hot, even with the
ignition off. 12VDC won't electrocute you but it may cause
burns or blow a fuse, so you may want to remove the
appropriate fuse or disconnect the battery before working in
this area.
Glenn Waterfield sends a description of how to rebuild
the joysticks: "I was able to very carefully remove
the pins holding the body of the switch together and strip
down the pieces and clean the corrosion off them. To
re-assemble the switch I did not want to try to reuse the
metal pins that originally held it together since I will
probably have to clean them again, so I found a tap just
barely larger than the pin hole, a 4-40 I think, and
carefully tapped the hole and put in three 4-40 nylon
machine screws. If you try this I would recommend a clear
work area with no carpet to drop the unbelievably tiny bits
and pieces into."
If you'd rather just get rid of the junk switches, the
following is a replacement scheme.
1. Make a flat rectangular panel to replace the original
chrome escutcheon (see Figure
17). You can make this out of anything you think
would look good in your car -- chrome-plated steel, sturdy
plastic, sheet metal covered with leather, elm burl,
etc.
2. Go to an electronics supply
store and buy four toggle switches. They need to be "mini"
or "submini" ("micromini" will also work if you find any,
but you need to drill smaller holes in the panel), "DPDT
momentary center off". This means that they not only need to
have three positions, but need to return to the center
position by themselves when released. The current here is
very low, a 3-amp rating will do. Once you find such
switches, they should be only about five bucks each.
Technically, a DPDT momentary center off rocker switch would
also work -- if you can find one small enough to fit four of
them in the car.
3. You may also want to buy some Molex connectors, such
as Radio Shack catalog no. 274-236 and 274-226, to replace
the hokey originals.
4. Mount the switches on your panel. The upper two should
be mounted vertically and the lower two horizontally, since
there will be one up/down switch and one left/right switch
for each mirror.
5. A soldering iron or gun is required here. Connect
wiring as shown in Figure
18. Note that each wire connects to two
terminals.
It is also possible to use only two DPDT momentary center
off switches instead of four by adding a DPDT switch
(non-momentary) to switch from left mirror to right. With
this selector switch, a center off position provides a
"lock" so the mirrors cannot accidentally be moved; while
not strictly necessary, it wouldn't cost anything, either
type switch is readily available.
Glen E. MacDonald went this route. "Not wishing to junk
the chrome escutcheon, I used the three switch alternative,
ie. two of RS 275-637 (one each for vertical and horizontal
adjustment) and one of RS 275-626 (to switch between left
& righthand mirrors). I found that the former switches
could be very tidily mounted where the original joysticks
were (in the escutcheon) by utilizing suitable diameter caps
from magic markers, pared for length and drilled to accept
the switch. The mirror selection switch is small enough to
mount unobtusively in the leading edge (front portion) of
the escutcheon. It works like a charm and, in my opinion,
looks quite professional!" Figure
19 is based on MacDonald's input for wiring these
switches. MacDonald cut the connectors off the original
switches, and therefore the illustration shows the
connectors and the wire colors from the original switches as
well as the harness wire colors -- note that some mirror
joysticks may have P wires instead of R.
Note: the author's local Radio Shack claims they no
longer offer the 275-637 momentary switches nor any
acceptable substitutes, but similar switches are available
at most other electronics supply houses. A suitable switch
is made by GC, part number 35-018.
It may also be possible to utilize the mirror switches
from some other car. More and more cars use electric mirrors
these days.
Once your mirror control switches are operational --
original or replacement -- it would be a good idea to wrap
some plastic around the assembly before installing to keep
rain that gets past the window seal from getting into the
switches and corroding the contacts.
The Electrical
System continues
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