Dear All,
I recently finished some bodywork repairs after been off the road for a few months. I had removed the front bumper, the right front wing and disconected the ecu and the brown plug with the leaver type clip to move things out of the way for sill repairs. Now the rear lights and number plate lights have stopped working. The bulbs look ok and as far as I can see the wiring has not been melted when we repaired the rear wheel arch. The brake lights and fog lights work fine. The wiring looks difficult / practically impossible to trace through the car so I am hoping that swapping the lighting module in the boot will do it. I checked the under bonnet fuses as indicated in the hand book. My car is a '95 XJR. Any advice appreciated.
Regards,
John

 

The wiring is known to have a weak point where it passes into the boot lid at the hinge. Apparently, constant opening and closing over time can cause the wiring within the insulation, to fracture, even if all looks ok on a visual inspection.
It might be worth taking a look see and is one of the easier and more obvious things to check out. Maybe access the wiring at the hinge area, switch on the lights and "wiggle" the wiring to see if anything happens.

Keep us posted.

 

Thanks, will have a look tomorrow. Would that affect the tail lights as well as the numberplate lights?

 

Doesn't sound like the hinge wiring unless you have two separate issues.

Could well be the rear lamp module but before you go throwing parts at it, you might want to check that it is getting signal from the BPM.

When you flip the lights on, you should have 12v at pin 1 of the larger connector on the lamp control module. If not you may have a wiring issue or perhaps a bad BPM.

Also check the ground points in the trunk.

If you haven't already done so, download the electrical guide from the 'How to' sticky at the top of this forum. It's free and invaluable!!

 

DOH!! Just realised that the tail lights aren't part of the boot lid, so they shouldn't be affected by dodgy wiring at the hinge! If you have power at the lights, then a bad earth might well be the culprit.

Apologies for the bum steer!

 

Thanks, Alan what is the BPM?

 

Body Processor Module.

 

I tried a few light modules at the scrapyard last weekend with no sucess same fault in each case. As all the other lights are working I guess the module must be getting power. The under hood fuses all tested ok but I will check all the others in case related. I guess the only other thing would be the body module or the lightswith but I would expect the headlights and taillights to be switched together and the headlights work fine. I looked at some of the drawings on this forum but I couldnt figure out if there was a seperate for the tailand numberplTe lights.

 

John,

The rear lamp module only controls the rear lights, the front have their own module in the engine bay. I would not assume you have power/signal to the module without checking with a meter or test light.

 

My 1998 had a broken wire in the headlight switch assembly

 

Thanks for all input. I ment to post earlier. The other week I got a replacement switch and board (with the foglight switches on it) from the scrapyard. Swapping the board solved the problem.

 

Which board are you referring to?

 

Hi, the rotary headlight switch is attached to a board which is accessable by removing the plastic cover below it on the bottom of the instrument cluster. There are some screws holding the board on and the fog light switches are also mounted on this board.