Please offer any ideas or solutions.
XJS 2+2 4.0 1994 tail light issues. On the rear fenders there are two lights on each side, the outer clear lens lights are turn signals and they both work. The inner red lens are a shared tail light and brake light and they both work. On the rear rear boot lid there are two lights on each side. the outer lights are clear lens and they are reverse lights and they both work. the two license plate lights both work. it is only the inner 2 red lens that don't work. The reverse lights and these two red lens share a common neutral. Bulbs, fuses, and relays are good. I am assuming that these 2 red lens are tail light only fixtures, The bulb holder sockets are good, as I tested these with a 9 volt battery and the filaments lighted up, but very weak. The wiring harness travels thru the boot lid and exits just above the convertible hood pump, it goes into the rear right fender well and then seems to head towards the front of the car. I would need to remove the fender well cover which hold the boot lid strut, to confirm. Is there possibly a relay I am overlooking?
John

 

Maybe just tap the feed to the two lid-mounted tail lights into the license lamps? They are/ should be illuminated at the same time….running light wattage is pretty low and I am sure the circuit can handle another amp or so.
Perhaps there is one of those silly “lamp out” relays for it, maybe under ski slope?

 

great idea thank you

 

Are you talking about the 2 "lights" next to the tag plate ?



These are empty dummy lights. Fitted to cars that dont have the long plates.

 

No I know about the dummy lenses, there is no light bulb fixture inside it. On your diagram the lights I mentioned are called the fog lights, which are just rear tail lights

 

No I know about the dummy's.On your diagram it calls them fog lights. I did not know tail lights / running lights were called fog lights. I see there is a fuse and a relay for the rear fog lights, I will check in the morning. Thanks

 

Rear fog lights are NOT your tail/running lights. Completely different. Euro laws require rear red fog lights in most countries, actuated by a separate switch.

 

Rear fog lights are NOT your tail/running lights. Completely different. Euro laws require rear red fog lights in most countries, actuated by a separate switch. Don't confuse the two. Separate bulbs, different portion of the lense, or a separate light fixture.

 

Thank you, On my xjs there is no seperate switch for fog lights, front or rear. i am hoping it is on the main head lamp switch. I also saw where there is a shorter plug involved, i may have to remove it. What is the purpose of the shorter plug?

 

The fog light switches are not part of the master light switch. There are separate switches for the front and rear fog lights beside the clock / trip computer. The switches are not there if the lights have not been specified from new.

Cheers

Paul

 

Even if the switches are not in place, normally the wiring is there. Same for the front fog lights.

 

Paul,
You are correct, to the left of the trip computer there are 2 rectangular buttons. One is for the rear fog lights and the other for rear windshield heater. The relay and fuse for the rear fog lights is under the driver knee bolster, both tested good, but I put in new ones anyway. the next thing to check I think would be the shorting plug, but what is its function and where is it located, and can I remove it? It probably goes thru the dash to the ski slope to the rear.
John

 

Ok, gotcha.
The rear foglights only work when the key is in run, the headlights are on and the switch is on. There will be a red light on the instrument cluster.

 

Thank you malc4d,
I was listening to the relay with key in run position, and no relay click. Then I got your message and also turned on the headlights and the fog lights came on. Your information is greatly appreciated and solved the problem.
John

 

I want to Thank everyone who offered me such good advice. I went from having zero knowledge of the rear fog lights to now having them light up.
Sincerely, John

 

Glad it helped. NOW instructions from an European lol. Don't just put them on and forget them, they are bright for the driver behind you. My rule of thumb is in heavy.rain, if see the car in front before l see the rear lights. l put on my rear fogs. Same in thick fog. Dont forget to turn them off when back in the clear....

 

yes, just as Churchill said, " the yanks will usually get it right, once they have tried everything else. lol