2001 Grand Prix Power Locks

I had a problem with my car leaking water in through the cowling above the AC/Heat blower motor. I have fixed the leak and replaced the blower motor.

When the leak was present my door locks would lock and unlock while I was driving and sometimes they wouldn’t lock when you put the car in gear, and they would not unlock when you shut the car off.

Now they don’t lock while I’m driving, but they also don’t lock when you put the car in gear and if I lock them they don’t unlock when I shut the car off. Is there a specific fuse that might have corrosion on it or something like that? I can’t find a fuse for just power locks. There are fuses for security, pass III and so on…

Would the fuse be in the car or under the hood?

My 2000 Century has several scenarios for door locks & engine conditions. These are user programmable. I’ll bet your Pontiac will be similar. Your first stop should be your owners manual which will explain them and the programming procedures. If you don’t have an owners’ manual, ask your dealer’s service writer if he will print the relevant pages from his service info system.

I have gone through the manual and all of the scenarios in the setup. According the dings in the setup the locks should be locking when I put the car in gear and unlocking when I shut the car off. But they don’t.

The schematics show just one 10A fuse underhood as supplying these circuits. They differ a tad depending on whether you have On-Star or not. I’ll assume not.

Another common point which controls these signals is the Body Control Module. It has a light green wire from the Park/Neutral Position (PNP) switch. If that wire were open, the BCM would get no signal and probably act as you are seeing.

OK, I will check the fuse under the hood.

How do I check if the BCM is not getting a signal? This may be related to another problem I’m having. Sometimes when I put the car in park and turn off the ignition, the key won’t turn back to come out. If I kind of tap the buuton on the shift lever while wiggling the key it comes out.

My doors actually locked once this weekend when I put the car in gear! They didn’t unlock though when I shut the car off.

Haven’t had time to check the fuse, but I guess it is OK since the doors locked. What could cause them to not work most of the time, but still work once in a while?

The problem may be due to a faulty connection somewhere and so the locks are intermittent. The best thing to do if want to work on this yourself is to get a service manual for the car. I recommend a factory one as the best to get. A good manual will save you time and money in repairs.