I'm not really sure how exactly to describe the issues, outside of just describing what it's doing, so here goes: It's a 2003 Chevy Blazer Xtreme, previous owner had a HUGE amount of sound system, A/V and alarm equipment in it that I have ripped out and done as much as I can to remove cleanly. I hope to get a stock wiring harness for it eventually, to just make it "done".

Anyways, the door locks. About 25% of the time they function correctly (hit the unlock button once, drivers door unlocks, hit it again, passenger door unlocks).

But most of the time what happens is I hit the unlock button, the drivers door unlocks. I hit it again, the drivers door RE-locks and the passenger door does nothing. If I continue hitting the unlock button, I can see the lock on the drivers door constantly re-locking. The only way to get it to unlock (with the remote, keys work fine by the way) is to hit the lock button, then the unlock button (which, if I hit it again, starts all over).

When I am in the car, if I put the car into park from drive, when this issue is happening the doors will not unlock automatically like they are supposed to, they stay locked and you have to manually unlock them. Sometimes the doors don't lock in the first place when the car is put into drive.

Lastly, the passenger door will not unlock when I hit the lock/unlock switch inside the car on the drivers door.

I owned a Volkswagen before this and had an issue with it where the door locks did funky things, that was caused by a bad central locking module, a separate computer that controlled the door locks. Crazy German electrical designers... I don't know if the Blazer has something similar? Or is this a wiring issue? I did rip out a bunch of the old (non-functioning) alarm systems and entertainment wiring from the car, is this some kind of weird security issue with the stock security system or something? I don't even know where to start with this :S


Thanks very much for any help or advice!

 

Alternatively, can anyone just point me in the direction of whatever computer controls the door locks so I can start diagnosing the computer or wiring?