The largest and best supported Jaguar cars enthusiast site on the Internet!

Serving Enthusiasts since 1993
The Jag-lovers Web

Currently with 3,166 members

Fog Light Wiring

Fog Light Wiring

Hi to all,

If anyone has recently done a rewiring job I would appreciate your comments.
Having hooked up almost all the wires to instrument panel and switches I
see that in the main wiring harness from the instrument panel to the fuse
box area that I do not a Number 42 wire (Red with Yellow)which shold run
from the light switch to the fog lamps. The harness which runs from the
fuse box area forward to headlamps etc does have a red with yellow core.
Has the harness manufacturer messed up and failed to put all the cores in
the first harness mentioned or am I missing a seperate harness which should
run all the way from the switch to the front of the car with only one plug
connector where the core splits to the two fog lamps.Looking at my notes I
made when I stripped the car down I believe I should have a seperate
harness. Any comments before I Fax the harness supplier demanding something
would be appreciated.

Neville Laing


I extracted my box of XK-140 OTS harnesses from the closet -someday they
will go back in the car. I believe that your cowl harness is correct, i.e.,
there is no Red with Yellow wire. My diagram shows a Blue and a Red wire
going from this harness to the light switch. Rhode Island Wiring supplies a
separate R/Y foglight feed wire ($14 in my old catalog). This feed wire
travels unbroken from the switch to the front of the car. I don't recall
where the front connection is made (hope I can remember when I have to put
it back together!). I don't have the R/Y wire in my engine harness,
contrary to yours.

Since the foglight was optional, I guess that Jaguar didn't install the
wire unless it was needed. Also, since I have a set of Rhode Island's
excellent harness diagrams, let me know if you are stumped anywhere else as
you go with the project.


Mike Carpenter

My XK140 has the red/yellow wire separate from the wiring harness. the wire
does not stop at the fuse box, but continues into the cowl past the
firewall. My wiring diagram shows the wire going directly to the headlight
switch (fog lamp position) with no breaks. I may have to drop my instrument
panel to help you further. Let me know if you need me to do that. (gives me
another excuse to change a dash bulb)
The setup requiring the separate foglamp switch uses the red/yellow wire in
the instrument harness.

Cleo Bay
XK120, XK140

You need a seperate "Foglamps Feed Wire", one end connects to 4-way
Lighting Switch (terminal 11), other end is bullet connector to a double
connector block. One side of this connector block takes Red/Yellow wire
feeding LH Foglamp; first side of block takes a seperate Red/Yellow
"Foglamp Crossover Wire" to a single bullet connector block, that joins
Red/Yellow wire feeding RH Foglamp.
Both "Foglamp Feed Wire" and "Foglamp Crossover Wire" are seperate
standalone harnesses, not included within any main harness.
Your "Instrument Panel" harness will include Red only feed wire to your
lighting switch.
All above only applies to XK140 Special Equipment that included Fog Lamps
as standard equipment, XK140's that had "Optional Extra" fitment I
understand from some reference sources had an extra Fog Lamp switch and
wiring differences, although I have not verified detail.

Roger Payne

do you know if the red and yellow wire which ran from switch to front of
car for fog lamps had a black or black and some other color braid over the
individual red/ yellow wire.
Neville Laing

My wire is a reproduction, but I believe it's authentic. When you say
braid, do you mean a harness loom or a black marker braided with the red
and yellow? Mine has no loom or braid. It does travel thru 6 foot long a
black plastic or rubber sleeve (conduit) where it routes thru the engine

Mike Carpenter

If you have any questions or comments send e-mail to:
Main Page Back to the Library


Please help support the move to the new site, and DONATE what you can.
A big Thank You to those who have donated already!



Go to our Homepage
Improve your Jag-lovers experience with the Mozilla FireFox Browser!

  View the latest posts from our Forums via an RSS Feed!

Jag-loversTM Ltd / JagWEBTM 1993 - 2023
All rights reserved. Jag-lovers is supported by JagWEBTM
For Terms of Use and General Rules see our Disclaimer
Use of the Jag-lovers logo or trademark name on sites other than Jag-lovers itself in a manner implying endorsement of commercial activities whatsoever is prohibited. Sections of this Web Site may publish members and visitors comments, opinion and photographs/images - Jag-lovers Ltd does not assume or have any responsibility or any liability for members comments or opinions, nor does it claim ownership or copyright of any material that belongs to the original poster including images. The word 'Jaguar' and the leaping cat device, whether used separately or in combination, are registered trademarks and are the property of Jaguar Cars, England. Some images may also be Jaguar Cars. Mirroring or downloading of this site or the publication of material or any extracts therefrom in original or altered form from these pages onto other sites (including reproduction by any other Jaguar enthusiast sites) without express permission violates Jag-lovers Ltd copyright and is prohibited
Go to our Homepage
Your Browser is: CCBot/2.0 (, IP Address logged as on 28th Sep 2023 18:47:01