Hello all,

The 1989 Park Avenue has random/intermittent issues.

The car will randomly unlock itself while started. Doesn't seem to ever unlock itself while parked and locked.

The car alarm will randomly go off if we leave it locked. Now we leave it parked and unlocked (unarmed).

The trunk lid was randomly popping open while sitting until I disconnected the cable to the release.

There is no rhyme or reason to any of this. I would suggest it isn't a loose connection since you can run down any rough road and there is no activation of the locks.

So far as I can tell this one did NOT ship with any sort of keyless entry.

So far as I can tell there are no other strange electrical problems.

Anyone have any ideas?

Thanks,
Jim

dont have alot of experience with older vehicles but i think they had separate alarm modules back then, since it all seems related to that i would imagine its something with that. if you can find info about your cars wiring colors you can add a aftermarket keyless or keyless remote start, they are less than 50 bucks for a basic setup these days

I think I might have a few items for ideas.
First off, it seems that every feature in these cars is controlled by a different computer, Alarm, Electric door locks/trunk release, oil change indicator, etc, all different computers. The book states that the computers range from up behind the glove box all the way over to the drivers side up behind the cluster. Only reason I know this is because I'm currently working out a project to convert from the granny cluster to a more modern cluster, without changing the dash. (jwfirebird remembers me looking through the archives about how to do this about 2 years ago. LOL)
To my knowledge, they shipped with this feature, but weather or not your car has the computer or not is up to what features were either installed, or ordered when your car was built and sold. My guess is if you know what computer is where, and what it does, and if you HAVE the computer that locks/unlocks the doors and releases the trunk, there are no remotes. You can buy the remotes from an online store or ebay. As always, be careful when ordering "used" remotes. Most of the time they are fried inside. My one remote would work, but wouldn't sync to the computer, so I got a new remote for around $10. It synced perfectly.
My guess is since your car decided to play demon spawn with you and randomly unlocks and releases the trunk, that you have that computer, but something is sending the signal to unlock, or there might be something wrong with the computer/wiring to cause it to randomly do this.
If you don't already have these, I highly recommend getting shop manuals.. Not the Haynes or other brands, get the Buick Shop Manuals. 89 is red, 90 is blue. I had to get both since my car is a split year custom job. I have an 89 interior with a 90 engine, and 91 electrical system. :/ (Thanks Grandpa! :/)

I am not sure if the older PA had memory button switch for the mirrors seat positions etc.
But...I had a similar issue where the doors would lock/unlock on their own.
I disconnected the battery positive and neg for 5 minutes restarted the car and then set a memory setting in, and the problems seemed to go away.
The Buick PA is sensitive to low voltage it seems as well.
Try to establish your AM voltage at battery after sitting all night.
The way I do it is to leave the hood unlocked, so you don't have a drain when u open the doors. Put a volt meter on it. Mine was reading something around 11.4 volts, which seemed low....drain over night? or battery?
When I first got my PA all kinds of electrical gremlins were happening, and with a midtronics load tester, the battery was analyzed as low on voltage.(even after charging)
Replaced the battery and things are all good now.

This one did have memory for the driver'* seat.

The seat track broke several years ago and when I replaced it, I pulled the memory module under the seat and never put it back - so at the moment the memory function is non-existent.

The problems started long after that, though.

Jim