This year has been very wet in this part of the u.s. (n.e. ohio). Coincidentally, the headlights on my xj40, s/n 706184) have been coming on upon start-up. Can usually turn off by cycling the headlight knob, but sometimes they come back on even when switched off, at various times. Is this a commonly-recurring problem on a car with 113.6k miles on it?
Car is stored inside 6 months of the year. Any input appreciated!

 

I dont think these had daytime running lights (did they?). I would suspect the headlight switch. It isnt a huge problem to get at, and as I recall is a fairly simple unit. There are controllers out front behind the headlights themselves, but it sounds like you have them acting as a set.

 

Canadian cars do Jerry, headlights on all the time. Maybe the OP's car wants to immigrate?

Larry

 

Hi Jerry,

At least some of the Canada-market cars had DRLs, according to the Electrical Guide. Since the headlamps each have separate relay/bulb failure modules (BFMs), I think you're right that the most likely suspect is the light switch module, or possibly the headlight flash switch in the turn signal stalk. Those are the two main points where both headlamp circuits come together.

If it's the low beams that are coming on, the main headlamp switch would be the first suspect. If the high beams are also coming on, then suspect the flashing switch in the turn signal stalk switch. The switches turn on the headlamps by connecting them to logic ground, so another possibility is a short to ground somewhere in the circuit.

The schematic is on pdf page 32 of the Electrical Guide, which can be downloaded here:

Jaguar XJ40 Electrical Guide 1993-1994

Cheers,

Don

 

Tnx for the info, guys! As I've not yet found my jag manuals to enlighten myself on the subject, I got lazy & posted. I got to the headlight switch & unplugged it, lights out. But I'll be damned if I can figure out how to get it out of there for further examination due to being blocked by the circuit board right next to it. Can't figure out how to get that thing out if the way.