Central Lock Issue - Random unlocking/locking/unlocking

[Cruisin']

Hi,
my '97 GMC has been giving me a bit of grief of late, electrical and mechanical...
The current issue is the central locking system.
I recently had a new passenger door mechanism fitted, as it wouldn't open from the inside.
Over the last week, both the door locking mechanisms have been randomly unlocking, on and off several times, then again a few hours later, day in day out.. for the last few days.
I have had 2 flat batteries over the last few months and was wondering if it's a case of buy a new battery...???
Or, is it something else doing this??

Has me beat...
Anyone experienced this or know how to fix it?
Any help would be appreciated.

First it was the indicators and interior lights randomly going off (I just pulled the fuse) this was ages ago and yet to sort that as the truck was my daily work transport.

Then the aircon actuator linkage fell apart, I am yet to sort that as I can't reach easily enough up under the dash to put it back together... I will work on that... almost need 3 hands..

I now have my other work vehicle fixed as a back up.

Any pointers or ideas would be greatly appreciated.

Cheers,
David

[Palf70Step]

It sounds like you have some short(s) in your wiring somewhere. For the doors, I would start at the door you replaced the switch on. Look for some wirings rubbing, bare. Tracing random electrical issues is a real pain for sure. Good luck with it and the other issues.

[Suburban Steve]

It sounds like you have some short(s) in your wiring somewhere. For the doors, I would start at the door you replaced the switch on. Look for some wirings rubbing, bare. Tracing random electrical issues is a real pain for sure. Good luck with it and the other issues.

The only problem I see in this would be that the "shorted wires" must be the EXACT 3 to cause both lock and unlock.. The locks work on a reverse polarity which basically means that for the system to work, wire the lock wire in energized w 12volts the opposite wire must see a ground.

With that said, you never know with electrical issues... Take a look at your actual switches I assume one is shorting out internally

[Suburban Steve]

OR...... alarm system? or factory keyless entry after thinking about it, this is most likely cause

[shifty]

I'm going to assume you're 100% positive the new door locking module replaced in isn't grounding out somewhere from the install, it's properly spliced with weatherproof/self-sealing beans or butt connectors or the stock connectors in good shape and not just twisted together and taped? When people start saying events are "Random", normally a short (unexpected ground) is happening somewhere. Whether that's under your dash from an aftermarket alarm, at the newly installed part, or at the control board itself ... options are limited, but still plenty.

If you removed the door lock/window control panel that sits in the door card when you swapped out things, that would be my first suspect, for whichever door it was removed.

First thing I'd do is remove the suspected panel, pop off the three harness bulkheads, check for bent pins, re-plug making sure it's firmly seated.

If no joy, you should literally be able to go to Pull-a-Part (or similar junkyard) and find a replacement control panel for under $20 to swap in temporarily and see if it works. If not, re-sell on eBay if you want to recoup, or return for a credit and find something else on the yard worthwhile.

If the none of the above works - that's just the way I'd attack it! - then I would start digging under the dash as suggested.