Electrical gremlins

My G/F's new XJ wagoneer (87, four headlights) has a strange issue with its headlights -

I haven't monkeyed with it enough to determine the exact and complete pattern but here's how it seems to work out:

Start with key in off position, turn on headlight switch, headlights turn on. turn key to run position, they turn off.

start with key in run position, turn on headlight switch, lights turn on SOMETIMES but NOT ALWAYS.

start with key in run position, turn off headlight switch, they turn off.

If you start with the key in run position, headlight switch in on position, headlights on , THEN turn key to off position, then turn headlight switch to off position, headlights stay on (we waited 2 minutes, just in case it was supposed to be on a timer for convenience... they stay on) ... but then if you turn the key back to the run position while leaving the headlight switch in the off position, the lights turn off.

Anyone have this before? Know how to fix it? Is it just a sticky relay or something?

There was an option called Headlight Sentry or something like that. Sounds like yours (hers) is messed up.

The way it's supposed to work is, if you have the headlights on, then turn off the ignition before turning off the headlights, the headlights will stay on for one minute to allow you time to get to the door of the house.

If you just turn off the engine and walk away leaving the headlights turned on -- you'll come back to a dead battery.

The control module for this just snaps into the wiring harness somewhere under the dashboard. You might try removing it to see if that eliminates the gremlins.

I know the XJ has a headlamp delay module, I'd start by looking for something like that and trying to bypass it. I'd give you a hint on where to find the thing, but all my FSM's are boxed up from our last move and I've not dug them out just yet. Anyone want to chime in?

There is no relay for the headlamps, unless you add one. The delay module is as close to a relay as you get.

5-90

For my 88 XJ the headlamp delay module has it own fuse, it is a 25 amp fuse. You may want to pull out the fuse and see if that fixes the problem. I can assure a blown fuse does not allow the delay module to work, found that out when my headlight switch died.

The electrical troublshooting manual says the C178 connector, used for the delay module, is located on the LH side of the I/P next to light switch. I do not know what the module looks like or where it truly located.

Try pulling the fuse, that should fix the problem. You could have a headlight switch which is at the end at it's life. If the fuse does not do it then consider changing the head light switch. I had to change my 6 months ago while I was 200 miles from home. Had to do it in the parking lot of the parts store at 7 pm, got to love it.

Thanks for the great advice guys!

I'll tear into that tonight when she gets home.

(working on a vehicle a couple hundred miles from home, in the parking lot of wherever, with a 2AA mag lite clenched in your lips? nah, NEVER done that!!! :spin3: