91 GP Power Options Not Working

Hey again all. Brandon here agian, with the 1991 Pontiac Grand Prix. The car has a 3.1V6, and power everything (locks, windows, mirrors, driver's seat). Well, yesterday, the Power Door Locks, Rear Window Defroster and the Power Seat stopped working. I was wondering if anyone out there knew of any reasons why these three things would stop working? Everything else works great.

All fuses both under the hood (unless there are more than the ones on the passanger side, at the front) and in the fuse box are in perfect shape. Under the dash, you can hear a 'clicking' sound coming from what I assume is the Door Lock Relay (it only clicks when you press the Lock or Unlock button), so I tried replacing this, but with no luck. For some reason, I also pulled out the 'Chime' module too, and the Relay stopped 'clicking' when you press the buttons with the 'Chime' module out, so I tried 2 other of these too, once again, with no luck.

Any opinions? Any fuses I could have missed? Do these 3 systems have anything to do with each other (as in, would they all be on 1 relay, or fuse?)

ANY help would be greatly appreciated!!!

Thanks All!!!!!!

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"One man can make a difference."
Wilton Knight - Knight Rider "Knight Of The Pheonix"

Sounds to me like part of your BCM is damaged.Have you tried to reset the computer on the car ?

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Jeff
Velocity Custom Home Theater
Mobile Audio/Video Specialist
Morden, Manitoba CANADA

Stupid question here, but what is a BCM? Is that the same thing as the ECM? I know what that is, and no I have not tried resetting it. How do I do that? Unplug the battery for 5 or 10 mins? If it is not the ECM, where can I find the BCM, and how do I reset it?
Thanks for replying so quickly.

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"One man can make a difference."
Wilton Knight - Knight Rider "Knight Of The Pheonix"

The BCM is the Body Control Module and it is not the same as the ECM. The BCM controls all the accessories and digital portions of the vehicle like lights, dash controls, door controls, HVAC, climate controls , etc....... If part of this module is damaged, then parts of the car will not function but other parts still react normally. You may be able to re-set the BCM like an ECM, but trial and error will be the best method here. Unplug the car's battery for about an hour and plug it back in. If there is no change in the condition, you will probably have to take it back to the dealership so they can put a diagnostics on the car to determine what is the problem.

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Jeff
Velocity Custom Home Theater
Mobile Audio/Video Specialist
Morden, Manitoba CANADA

Ok thanks. At least I have somewhere to start now.

But, I do have a couple more stupid questions. I have never heard of this, and I have talked with a couple of mechanic shops, and they can not find any BCM listed on there computers, or in there books for a '91 Grand Prix. Are you sure there is one on this car? Do not take that the wrong way, I just wanted to make sure you knew it is a '91 not a '01.

Also, if it does indeed have one (I am going to try the battery reset anyways, tonight, weather it has one or not, I will still try it tonight), where might I find it, if you happen to know? If I can find the thing, and the battery reset does not work, I will just get one, and try it. If it works, great. If not, perhaps to a dealership for diagnostics.

Thanks again, you are being VERY helpful!!!!!

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"One man can make a difference."
Wilton Knight - Knight Rider "Knight Of The Pheonix"

Hey again. I posted this a while ago, but it does not seem to be showing up. So I will post it again. lol

Just wanted to say that I checked, and my Grand Prix does not have a BCM. Thanks for the suggestion though.

I was also wondering, if you or anyone else out there have any other suggestions?

Thanks again All.

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"One man can make a difference."
Wilton Knight - Knight Rider "Knight Of The Pheonix"

Find the wire that is SUPPOSED to supply the power to the devices that are not working and attach a wire that has a fused 12 volts on it and a test the devices. If you know which wires are supposed to have power to them, but they don't then add power to them and see if the devices work afterwards. If they do, then chances are you may have a burned out relay either in the engine or under the dash area.

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Jeff
Velocity Custom Home Theater
Mobile Audio/Video Specialist
Morden, Manitoba CANADA

Ok, this is weird. This is the second time I have had to re-type a message. lol Well, anyhow, I will get over it. :-)

Ok, well. lol. I started the car this afternoon, and the locks and seat worked fine. Tried the defroster, and it came on for like 1 second, and then all 3 stopped working. A couple hours later, the locks and seat was wroking again. Tried the defroster, and same deal, this time there was a 'buzzing' sound when it was on, for the 3 or so seconds it stayed on. An hour or so later, the locks and seat worked again. Tried the deforster, and it made that 'buzzing' sound again, so I shut it off after about 3 seconds. The locks and seat kept working. Well, got home, about 30 or so mins later, and ripped apart the bottom panel (under the glove box, where all the breakers (if that is what those silver 2-pronged things are called. That is what I was told, sorry if that is incorrect) and the lock relay, and the defroster 'clicking' thing is. Switched on and off the defroster till I found out which 'thing' was 'clicking'. Pulled it out. Locks and seat still worked. Defroster did not (obviously. lol). Put it back in, and all 3 worked fine. No buzzing, just the 'click' it makes when you turn the froster on or off (same as my old '92 Grand Prix did) and the same this car has always done, as has all my other cars, and every other car I have encountered, so I guess this is usual. So, I looked at some of the wires. Well, there is a purple with a white stripe running down it, wire connected to the breaker that the 'clicking' defroster thing is connected too. So, I looked at where this wire went, and found it was split off to 2 other wires. Both same colors, but one was smaller. I took off the tape (NOT electrical tape, some cheap crappy tape. lol) and noticed where the 3 wires meet, was all terrible. So, I snipped them all. Locks and seat still worked with wires snipped. I then reattached the 3 wires, and now all things are still working.

I am sorry, but I just do not get it. If it was these 3 wires making the 3 things stop working, how come when I snipped them (they were not connected at this time) the locks and seat kept working?

Well, I am just wondering if you have any other opinions on this matter. Should I just leave it, and see how it goes? Should I take it in and get it looked at? Do these 3 systems have anything in common?

Thanks MUCHLY for all of your help and opinions.

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"One man can make a difference."
Wilton Knight - Knight Rider "Knight Of The Pheonix"

That "clicking" thing is a relay and what you should do is replace it with a new one. It may be failing sometimes and cutting out your defrost . It seems that from what you are saying above, that would be the problem piece.

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Jeff
Velocity Custom Home Theater
Mobile Audio/Video Specialist
Morden, Manitoba CANADA

Ok thanks, that is great. But, I still have a question (pardon me for being a pain). If the problem was indeed that relay, why when I pulled it right out did the 2 other things still work? Plus, (and I just remembered this again), I did try 2 new relays, identical to the one that was in the car, and neither changed anything (this was a few days ago, when all 3 were not working), all 3 still would not work.

I do not know. This car is weird, with a capital "W". lol

Thanks for your help though, the car seems to be working perfectlly now, but I will go out and buy a relay, just in case they stop again, so I will have it handy, to change if it does so.

Thanks again for all your help. MUCHLY appreciated!!!!!!!! :-)

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"One man can make a difference."
Wilton Knight - Knight Rider "Knight Of The Pheonix"

Good luck witht he vehicle.... that is one wired problem you have there ...

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Jeff
Velocity Custom Home Theater
Mobile Audio/Video Specialist
Morden, Manitoba CANADA

LOL!!!!!!! It is not only a weird problem, but a weird car to begin with...Oh, the stories I could tell you about this car, and I have only owned him for a little over a year...lol

Well, anyways, thanks A LOT for all your help, I now know where to come with my questions!!!

Thanks!!!!

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"One man can make a difference."
Wilton Knight - Knight Rider "Knight Of The Pheonix"

No problemo... have a good holiday and better New Years

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Jeff
Velocity Custom Home Theater
Mobile Audio/Video Specialist
Morden, Manitoba CANADA

Hey again. I do not want to take up bandwidth, or waste space or whatever, but I just had to thank you again, and say you had me rolling on the floor laughing at those emoticons!!!!!!! LOL!!!!!!! 

I hope your holiday and New Year's is great too!!!

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"One man can make a difference."
Wilton Knight - Knight Rider "Knight Of The Pheonix"

Thanks and New Year's will be good for me

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Jeff
Velocity Custom Home Theater
Mobile Audio/Video Specialist
Morden, Manitoba CANADA