Body Control Module on a 1993 Ultra

In the mornings, when it's cool, the doors don't lock and unlock by using the "shift out of Park" method. Later, when the car warms up a bit inside, the feature of lock/unlock works fine. Rear window defroster doesn't work either when it's cold out side, but will work when it warmer.

All things are pointing to the BCM or Body Contol Module that may be faulty. Several people have told me this, but I have taken out the glove box, and also the cover under the dash on the passenger side, but don't know exactly what the BCM looks like. Any clues??

A wrecking yard here has it available for $50 but I need to figure out what it is I'm replacing, first.

I have a 1993 Buick Park Avenue Ultra *with supercharger

Thanks
Vernon
[email protected]

Well, I'll post to my original post since there is an update. I bought a used BCM and it works pretty well. The only thing is I had to clear the memory from the module underneath for my 2 key fobs, and program them all over. Next I have to take it in to the Buick dealership to have it programmed. Around 85 bucks/ 1 hr to do. Doors lock when taken out of park but won't unlock when put back into park. All else seems pretty normal. Rear window defroster doesn't work, but may after the re-programming.

:grinyes:

The issue of doors locking and not locking when it's cold still remain. Really oddity. When I shut it off and wait for a few seconds I can hear a faint "ting-ting, ... ting-ting ... ting-ting" and then the doors will lock/unlock with the remotes. Really odd thing.

the main circuit braker # 4 feeds the power to these and also the power seats. check this out first ok

Oddly enough, I noticed that when I turn off the "Twilight Sentinel" and just turn on the headlights manually, if needed, I don't get the same problem of cool weather causing the doors to lock and unlock.

When it does decide to quit working, then NO door unlock mechanism work except manually unlocking. Example: I park the car and doors remain locked. Press the unlock on the side of the door and you hear it click under the right passenger dash area. You try clicking lock / unlock with the remote and you still hear the clicking sounds come from that are but no response. Open up the left (drivers side) rear door, and THEN click the remote and 9 times out of 10 the doors respond as normal. Once this is "overcome" then the doors behave as normal and cease to stick.

if you hear a click it's the bcm grounding the door lock relay. that's suposed to happen. then the power goes from c.b. #4 to the unlock relay and to the solinoids. also if you want to have the doors unlock when you shift back into park you need to progran it. to do is to get in the car and turn the key to run, step on the brake, hold the power doow unlock button in and shift the car out of park and then back to park. let go of the door lock, brake pedal and shut off the car. then try it ok.

I programmed it long time ago to unlock when I put it in park. That info is found in the owners manual. What would be nice is to NOT have it lock at all when you pull out of park into reverse. Then it wouldn't matter if it unlocked or not.