Hey all,
I did a search and found some good posts on brake lights but can't seem to narrow down where the fuse is for them. Ive seen some posts say the fuse is in the trunk. I've pulled the carpet from behind the back seat, there are quite a few in-line fuses back there. Any advice on which one to look at would be great.

Thanks!

 

Series III car or ???

Cheers
DD

 

Yes Doug, series III. Sorry

 

Left scuttle on my 83 XJ wuzza 6.


And, after a lot of other stuff, I'm convinced, it was the ignition switch!!!


So much on these cars is related to the ignition switch!!!


A replacement fixed a ton of stuff on my car.


Not to say that is your issue.


The brake light switch is also a candidate. Tough to reach.
Been there, swapped out.


Carl

 

Check every fuse. It could be the brake pedal switch like Carl said. There are 2 switches behind the Brake pedal, the one to check is the one on the left, it is known to fall apart but it can be removed, and repaired.

 

Oh, oh, I thought it was the one on the right that governed the brake lights.


Important as the logic is reversed between the two!!
The one on the left s for cruise interrupt. Default is closed.
Application of the pedal opens the CC circuit.


Carl

 

Yes sorry, the left switch with the yellow/white wires is the Cruise off switch.

 

Thanks for the replies. Tracked it down to the driver side fuse box and the horn/stop light fuse. I replaced it and it worked for a while then blew again. Any ideas/thoughts on how or why it's popping the fuse? (obviously overload) but, where should I look?

Electrical is pretty complex...

 

Yes, I'd suspect an area where mechanical movement and
wires are close.


You will need the S 57 Jaguar electric schematic publication. O'wise you are flying blind.


1. The stop light switch and the brake pedal.


Might take some panel opening.


Drop the scuttle on the driver side to track the power from the ignition switch switch to the brake light switch. Probably a white wire.


Remove the cover on the A pillar. You will see the route of the wire from the BL switch back top the reverse lamps. As a last resort, open that wire and see if it will accept fused volts with no blow.


Remove the inline switch over the battery that power the horn
if it the horn circuit that has a short, that will open it. try anew fuse and operate the brake pedal and see if the fuse stays intact.


Look, actually more like feel around the brake light switch with the pedal down for heat denoting a short in the BL switch or the wires near it.


Less likely, in the boot, behind the lamp receptacle.


Tis a matter of isolating parts of the circuit til one finds the "bare spot in contact with another wire or chassis.


Carl

 

I just had this problem on my series 2. The brake lights would not work and the fuse would blow almost immediately after turning the ignition on. It turns out the battery cooling fan, kickdown switch, control circuit for the AC coolling fan on radiator, and a couple of other things are on this same circuit on a series 2 car. The first indication something was wrong was my car as running hotter than usual. I checked and the cooling fan was not working on the radiator when the AC was on. Then, I discovered the brake lights were not working.

After trying a few fuses, which immediately failed, I started looking for shorts. It turns out I had disconnected the battery cooling fan motor wires, previously, and I missed one that was trapped under the battery box. Over time, it wore through and shorted. All the wires to the fan have a little plug, so I disconnected the plug for the last wire and the fuses stopped blowing. You can use a multimeter to check if a wire is shorted to ground by checking continuity of the wire and the body or negative terminal of the battery. I hope this helps. I was very lucky it was something easy.

 

ooops, It isn't a white from ignition to brake light switch. It is white from ignition switch to the fuse panel.


The wire from the fuse panel to the brake light switch is another
color. I forgot which. check the s57 schematic. Gotta have one....


Carl