I got pulled over for the first time a few days ago due to my tail lights not being on. As far as I was aware they were supposed to be on because my headlights were on. but then I also noticed my interior lights like my Instrument Cluster, my gear selector, my Trip calculator all aren’t lit up. But when the cop pulled me over and the car was not on, all of my lights worked, headlights, tail lights and interior lights. I am a relative newbie to this car so I don’t have any clue what the problem could be.
My gut feeling is that you have a bad ground. I’d just about bet money on it.
But where to begin the search? I’d go to the trunk first.
From memory there is a ground point inside the trunk at each tail light…should be easy to find. Then, on the RH side, further forward, in the vicinity of the ECU or battery, is another main ground point. Check/clean/tighten the grounds.
(As you wok on various parts of the car I suggest cleaning every ground you happen across. it only takes a few minutes and you’ll be pre-emptively solving about 80% of the much ballyhooed “Lucas, Prince of Darkness” problems)
Others might have more specific info. I’m on my first cuppa coffee, sold my '88 XJS years ago, and am getting old
You coul make a test wire with alligator clips and put one end on taillight ground wire and the other to a good clean body bolt or even to the battery negative. If everything works then its the ground…any local mechanic could do this in five minutes.
Hi Maxine, welcome to the interesting world of Jaguar wiring.
All of the lights that failed on your car get their power from the same terminal of the lighting switch. (Clue #1.)
From looking at the schematic, all of the circuits appear to run through a connector (CP7) which is located in the center console. (The mass of wiring around the base of the shifter) Clue #2. When you shut the engine off, all the lights worked again. #3.
I would guess at a loose or dirty connection at the switch, or the connection below the console.
How are you with a test-light?
( A few inches behind the light switch there is an eight-pin connector. Could be as simple as that.)
So I found the 2 behind the tail lights, one’s in front of my Radio antenna thing. How do I go about cleaning them? just normal ground wire cleaning? I never know if I need to do something special for this car.
The really odd things about jag xjs are plumbing electrical heating and air conditioning… sort of a hvac issue with electric and plumbing thrown in. My local mechanic just says bring it in and we’ll fix it and they are not specialists. …good mechanics…I dont think the car is as mysterious as you think especially because of all that plumbing over the engine…it has its faults as does most models of any car.
