Interior lamps will not turn OFF

[patrick66]

In my son's '85 Grand Marquis LS, the interior lamps and the keyhole lamps will not go out. Normally, all of these go out once the ignition is turned ON, or time out in approximately ten seconds. The only way they go out is if we pull the bulbs...and then, the door lock lamps do NOT go out unless we pull the ground off the battery. I've eyeballed all four door switches, and the RR door switch has no "spring" to it.

Any ideas???

[L1011tristar17]

Is the headlight knob turned all the way to one side? The knob acts as a dimmer switch, and if turned all the way bright, it will turn on the interior lights. You'll feel it click into place.

[gadget73]

usually if the door switch doesn't spring out, it will keep the lights from coming on when the door opens, not the other way round. Worst case, you can unplug that switch to see if the problem goes away. The headlight switch is definitely the easy thing to check though.

[BerniniCaCO3]

ditto. felt like an idiot when I did this.

possibly a door switch could be bad (if you check the above and you weren't an idiot like I was).
Only way is to start pulling them and and seeing when the lights go off. Maybe starting with the suspect one. Keep a grip on the wires you don't want them falling back into the pillars.

[BerniniCaCO3]

lol seems gadget and I posted at the same time.

[patrick66]

The very first thing I checked was the headlight switch, and it was positioned normally (no interior light). Turning the key ON does not shut the lights off inside. We've "popped" the door switches (pushed in and then "popped" them out) to no avail. So, now, the only courtesy lamps working inside are the switchable dome spots. We've pulled the other bulbs. The door lock illuminators still stay on, necessitating the removal of the battery ground when parked overnight.

[sly]

possible the relay for the entry module is welded shut and needs replacement. I think it's located behind the passenger side kick panel. Put the bulbs back in and search for a hot relay. If that's not the problem, it could be the entry module itself. Not sure exactly where that thing is located as I've never had issues with mine.

[Stocker]

The manual seems to imply that the module is under the dash near the center of the car. It's whatever the hell it means by "mounted to the upper part of of the cowl top inner panel brace in the vicinity of the tunnel and can be serviced from beneath".

I had a similar issue with the lamp module in a Taurus wagon once. Ford's Better Idea™ on that car was to mount the module above the rear wheelwell so after it rusted through, the module would get wet, corrode, and have a conniption fit. On mine I found the car with all the interior lights on, flickering every 10 seconds.

[sly]

that means behind the ashtray. That's where the autolamp relay lives in my 88. how fun.

[patrick66]

Right now, we have simply pulled the fuse for the lights. Of course, the clock, power locks and a couple of other things don't work now, either. I'll just have to search for that module later.

[patrick66]

Does anyone have a factory service manual, to where I can locate this module? The car has only been driven a few times in the last six weeks or so, and I'm getting ready to do a few things to it very soon, so now is as good a time as any to dive back into this.

BTW, the Merc does not have the AutoLight feature.

[86VickyLX]

The module is bad. I've had seen this with an 84 Crown Vic. If you turn the key to run after the door is open and then turn off the ignition, the light should stay off. The relay is probably sticking in the module. I'm not sure if that can be repaired or not. But at least your lights won't be on all the time.
The module is located on the passenger side of the dash, either under the glovebox, or in the passenger kick panel. I think it may be blue in color. Can't remember.

[patrick66]

I'll search for that puppy today, thanks