XK8 - MY98, 90,000 miles. Electrical issues are truly the bane of my existence. My question is relatively simple, is there anyplace that the ground for the tail lights and trunk (boot) lights are common? The problem is at times (+/- 15%) I get a rear tail light failure (left or driver's in US) when I switch on the lights for the car. I will drive a mile or so and the tail light comes on and the failure off. About 10% of the time the trunk lights will work, the rest of the time, they do not. By the actions of the two I would imagine that someplace there is a lose ground wire, but looking at the wiring diagrams, I do not see where there might be a common point. Or am I chasing two independent problems?

Thank you in advance for any thoughts.

 

The ground on early tail lights are known to be inadequate and can melt things. Check out this thread to add an additional ground: https://www.jaguarforums.com/forum/x...esolved-35083/

Another issue I discovered is the lamp control module. Here is thread covering my issue, see if anything in there is helpful for you too: https://www.jaguarforums.com/forum/x...issues-216216/

 

Thanks much K.Westra. Frankly even if that is not this problem (I'm not saying it isn't) adding the heavier ground sound like a really good idea. In your opinion, where is the best place to attach the ground wire to the body?

 

NevadaXK8,

The trunk lights are a BPM controlled ground, so don’t have a body ground. If you have a voltmeter handy check you can check the voltage on one of the connection pins to the bulbs. Should always be 12V.

So I think you have 2 separate problems. Common fault for the trunk lights is a bad micro switch on the latch or in rarer cases the diode, which in my case was on the wiring loom above the battery.

Radjag1is having the same problem and here’s a link to his thread with photos and diagrams.
https://www.jaguarforums.com/forum/x...lights-234271/

 

David, I will check the voltage on both sides of the the lights. I viewed the trunk light thread a bit earlier, and like you, I thought this may be two problems ganging up. If I do get the correct 12v. on both sides as the video shows, I will chase the micro switch.

On an unrelated topic, do you have a cooling issue there in Bahrain?I'm here in Las Vegas and the 110 - 115 degree F (43-45 C) temperatures are typical. Your humidity I am sure is ten times (10% typical here) what it is here and always worried about overheating. Will be installing RealGuage on the temp side soon so I can sit there in traffic and worry a lot.

 

Funny you should ask that as I just did a cooling system overhaul on my 99 XK8. Documented in my thread below. It was preventative maintenance as I was having minor leaks at the front and already R&R the octopus at the back 2 years ago.

https://www.jaguarforums.com/forum/x...em-r-r-234389/

Yeah, it’s common for older cars here to overheat. If I’m driving around during the day, it’s a common sight to see a car pulled over, bonnet up and steam coming out. I’m pretty sure that it’s because shops here only stock green coolant so people are unaware of the problems of you mix red/orange/green coolants.

Humidity in the evenings here is real bad too, and you have the classic problem of condensation on the windscreen. You have to pop the window a bit to clear it- which is a problem as night time temps are still around 32DegC.

Realgauge is on my ToDo list too. Yet to order it, though. Nothing to worry about as any additional driver info is good esp. as our AJ-V8 overheating is a potential engine killer.

 

Thank you for everybodys help! Happy holidays.