99 Grand Am GT Electrical Problems

[Guodian]

I've had to replace my alternator 3 times in a year and a half. It has been about a week since I last replaced it and I'm now again having electrical problems that seem like alternator issues.

Here's the problems:
-Power fluctuations, dimming lights after turning on the heat, etc.
-Complete car shutdown without much warning (without any dimming of lights etc.)
-Dashboard warning lights randomly turning on then sometimes turning off.

I was also told by the pontiac dealership where I took the car that the alternator was not charging up the battery at low rpm's at first, but is now working perfectly... They also checked the battery and starter, and have no answers as everything now seems to be working perfectly. Bummer.

So hopefully someone has seen problems like this before, and if so I'd really appreciate any advice you can give-

[mcrosby]

In my opinion, the dealer has not found the original problem or they have repaired the car improperly. Allow me to explain my experience with GM alternators. I owned an Olds Calais that ate alternators. Every year I had to buy a new one, and as you know, they are not cheap. To make a long story short, there were two problems.

• The wrong alternator was installed.
• The alternator was very close to the exhaust manifold and was literally cooking the altenator.

Both Sears and O'Rielly sold me a 70 amp alternator and my car called for a 100 amp alternator. They look identical. For the heat problem, I cut out a medium thickness piece of sheet metal, drilled two holes in it, and installed it under the alternator using the alternator mounting bracket screws that are screwed into the block. I never replaced another alternator the rest of the time I owned the car. So, I said all of that to say, the dealer has not found the right fix. I would hold their feet to the fire on this and don't let your warranty on the car or the repair expire. Document all your repairs and symptoms, and who you spoke to. That holds a lot of weight when you speak with management or, if it gets that far, the judge. I would be willing to bet that altenator is bad again and if not it will be soon.

[Hoags]

Welcome to the forum:

Man the problem your describing is a tough one. If I understand properly, the dealer says that the alt is outputting a charge to the battery, but yet you seem to loose the stored power? I am just guessing here, but has anyone done a test for a power drain on the system? Meaning is it pulling too much power when the car is running thus draining the powre taster than it can be replaced.

OK, Something just came to me... I had an old Pontiac Catalina(yes I'm going way back) but I had alt issues with that, it took a long time to find the problem but what it finally came down to was the drive belt. The belt was too loose and well worn (very well worn) and it was not able to spin the alt enough to crank out the amps on any thing above an idle or a little more rpm's, This is just a thought but check the drive belt, maybe it is slipping on the alt pulley! Hell it's worth taking a look at.

I hope this helps, I am sure other members will give you some more ideas to look at.

Good luck...And Again welcome to the forum.

[Guodian]

Thanks a lot for the advice guys, I'll make sure the dealer checks on the problems you mentioned (alternator near exhaust manifold), (correct amperage on alternator), (power drain), and (belt wear/tightness). I do have access to a machine shop, so if the placement near a hot engine part is the problem I might be able to copy your fix.
I'll definitely be back if I ever need advice again, you've been very helpful.

[gmack221]

Just a side note, when I bought my alternator for my 97 s10, at the parts store they told me to make sure the battery was completely charged or I would be bringing that alternator back. They told me some story about the alternators having a computer chip in them, and if you have a dead battery it will fry the computer chip trying to charge a dead battery. Any truth to their story? The other thing I noticed was they have strict instructions as to which wires to hook up first, basically amounts to you should have the alternator mounted, then hook up the positive battery cable, then plug in the larger clip to the computer chip. I've put on alot of alternators and this was my first run in with these instructions, maybe there BS, but the company spent alot of money printing up stuff to document this, so obviously they've had problems in the past with this. Could this have happened to yours? Did you install it or did a shop, or dealership. just my