Hello all ...

'94 XJ-S convertable (6 cyl) just back from a (terrible) mechanic and now the brake lights (all three) are not working. I replaced the blown 15 amp fuse, and as soon as I touched the brake pedal, the brake lights came on for a half-second and the fuse blew again. Repeated this with same results.

The mechanic may have been rooting around in the trunk, as he replaced the battery.

Before I tear apart the trunk in search of crimped or burned wires, does anyone have any suggestions? Is there a brake light relay somewhere to check first?

Thanks!!

Mark

 

Hi Mark,
Have a look behind the left trim panel in the trunk. Above the ABS ECU you should find the stop light relay RH113.

Sounds like you have a short on that circuit.

Hope this helps,

 

Easiest way to find the fault if you have a soldering iron is to take one of the blown fuses and solder a 60watt light bulb across the fuse and put in the fuse holder, this will light the globe if the current draw is too high allowing you to find the source of the high current draw.

Next alternative is to remove all of the brake light globes and replace 1 at a time until you find the offending faulty globe. It will be one of them drawing too much current.

 

This might sound like a dumb thing, but did the mechanic replace the battery with an appropriate one? As a "professional Jag mechanic" (note the quotes), he may just put in whatever fit or one he had around instead of one with the proper Volts and Amps. I'd check that before assuming he did something to the wiring.

 

Thank you ALL! Will investigate in the morning!

 

I would also check the high mount center brake light on the trunk lid....... the wiring inside there is "interesting" to say the least. There is very, very little clearance between the positive and the negative wires (which are bare) so it's easy to get a short there.

This happened to me a while back and it took me ages to find the problem. What I think happened with me was that as the trunk is opened and closed, the vibrations caused the connections to move until eventually they touched. I think the fact that my trunk struts were shot and it was easy to "drop" the trunk shut, sometimes from a greater height than I should have probably accelerated this failure for me.

While I was in there fixing the connections I put as much electrical tape as I could around the exposed pieces of metal to hopefully make it more difficult to fail again