Hi All!
My '99 XJR warning lights and various feeds from the ignition circuit will not switch off with the key. The engine starts, runs and stops OK, the generator generates and it's warning light operates correctly. I've tried replacing all the various relays, all the electrics are working OK apart from this fault which has just occurred since we had sub zero temperatures outside.
Help please!!!

 

I have just experienced the same problem XJ8 2002. Is it due to temp ? Lights came on and diagnostic ran will not shut off on key, battery is drained, will charge it and try resetting (rebooting computer) Car was not driven for three days sat in below freezing temp. saw lights on and discovered problem turned lights off but diagnostic still ran. Any suggestions?

 

hi everyone... I've just found the problem and remedied it, thank god! It was water in the engine compartment front fuse box.
I disconnected the main feed wire to the box, slotted the box out of the holes on the wheel arch by pushing it forward and lifting, disconnected the 4 multiplugs, removed all relays and fuses and prised out the inner plastic mounting piece allowing the printed circuit board to be removed. I found it had been arcing around numbers 5 and 6 fuses on the p.c. board.
I've cleaned dried out and cleaned up what I can, on the board and sprayed WD 40 around it. Put it back together and hey presto...
I'm not religious but I thanked God for also driving a Jag and being able to guide me...just in case!!

 

happy to report a little WD40 on key and a battery charge got everything back in order!!! Battery seems fine and everything is working again, so glad.......

 

That's good to hear you fixed your problems , feedbacks are appreciated