All other rear lights working perfectly. Had an interesting experience. I live in a very hot summer climate. My XK8 has been kept in my garage when not drivng for the last 20 years but this summer no garage available. The plastic bracket that holds the rear view mirror melted and the melted plastic ran down into my jgate. Unbelievable right? It happened. Is it possible some damage or any interference could have caused both the high mount and the rear fog lights to cease functioning? I've pulled and replaced the relays and fuses for the rear lights but no change. Any other ideas greatly appreciated. If a loose wire is the issue how do I track down the culprit for the high mount?

 

Are you sure your lights were working before the mirror bracket melted - sounds like coincidence or the high temperatures melted something else. You've already checked the relays and fuses, so the next step is to try jumping the relays and see if the lights come on. Another simple check is to make sure you have power and ground where you expect it to be in the trunk fuse box - you need a multimeter, or even better, a test bulb to check that.

 

Thanks for the reply. Yes, the melting of the bracket was probably coincidence. Rear fog lights are now working. Recently changed out all the bulbs in the rear. Could there be a polarity issue that's effecting the high mount? How do I check with a test light? And how to jump relays? Sorry if these are stupid questions but just trying to get it all figured out.

 

If it is only your high level brake light that isn't working, it's likely to be a break in the wire at the boot lid hinge, or it could be the light itself has failed. Have a look on YouTube for a tutorial on jumping relays - basically you remove the relay and using a piece of wire short the contacts side of the relay socket together and see if the light comes on. If it doesn't you move on from there and test at the light itself for power.

You need a multimeter and ideally a test bulb - literally a 12v bulb with two wires that you can use to test for power.

If you have a search on the forum you will find other threads about the third brake light as you are not the first to have this problem.

 

Thanks for your reply once again.. Precisely the direction I needed. I'll let you know how it goes.

 

FOUND. Not one but two broken wires, the red and the black at the boot hinge. How is it possible for two wires to break when the high mount was working perfectly only 2 weeks ago when the issues with the rear lights started. It's a Jag. I suppose it happens. Thanks again for your help.

 

Well done for finding the fault. This just shows how tight Jaguar's quality control was back in the 20th century - both wires failed at the same time after 25 years of boot opening and closing.

 

Very true. I've had the car for 20 years and it's been basically trouble free. A couple of brake light switches and gasket replacements which allowed the opportunity to replace the plastic tensioners with metal. The car just turned 80K miles. My mechanic was the service manager when there was a Jag dealership here 25 years ago and is about to retire. Hard to get the car in to seeing him as he's too busy. I think I will get an electrician to repair the two broken wires as a permanent fix. The only issue I have now is finding somewhere in he US that makes the seat covers. My driver seat is shot. Passenger is fine but wouldn't look right only doing the driver side. But that is for a new thread.