94 Park ave. alternator question

My dealer has replaced the alternator and battery on this car,
yet now whenever I drive it any distance the little red light
beside alternator gauge come on and off. Sometimes it stays
on solid others just flashes on and off.
The car starts and runs fine and the gauge seems to work
correctly.
Any ideas what might cause this, and any reason to worry
about ruining this new alternator ?

Thanks,

Is the plug on the back of the alt plugged in good?

Are the battery terminals clean and on good?

Is the positive coming from the alt tight?

Have you called the dealer to ask why? Seems your problem started after they did their work on it. If I could figure out why mine is doing something simular to this I could help you more, this is all I can think of for now. Good luck! And welcome!

Is the plug on the back of the alt plugged in good?
Not sure, will check today

Are the battery terminals clean and on good?
Yes

Is the positive coming from the alt tight?
Yes

Have you called the dealer to ask why? Seems your problem started after they did their work on it. If I could figure out why mine is doing something simular to this I could help you more, this is all I can think of for now. Good luck! And welcome!

Took it back to dealer, and of course during their short check it worked
fine for them.
Thanks,

I have the exact same issue on my car.
The voltage light has been coming on and off randomly for a couple of years now, but without apparent reason. Never had charging problems.

Recently, I had to replace the battery. A little later, the alternator started acting up (the voltage dropped while driving), so I replaced it. But that did not help, the new alternator did the same as the old. So I replaced the PCM, and that finally solved the problem. You have to know that the PCM controls the exciter wire to the alternator. Somehow this circuit must have gone bad...:dunno:

So, to cut a long story short: I replaced PCM, alternator, battery, and still have the problem with the voltage light! But charging and voltage levels are absolutely OK. Therefore I am almost certain the error lies in the instrument cluster. I removed the cluster and resoldered some ICs, and this helped for a short time.
I suspect an IC being bad on the cluster board, or the PCB itself has a faulty connection.

My 92' has had that light flash (never stay on) from time to time. No charging problems, and voltage always read fine.

I have the exact same issue on my car.
The voltage light has been coming on and off randomly for a couple of years now, but without apparent reason. Never had charging problems.

Recently, I had to replace the battery. A little later, the alternator started acting up (the voltage dropped while driving), so I replaced it. But that did not help, the new alternator did the same as the old. So I replaced the PCM, and that finally solved the problem. You have to know that the PCM controls the exciter wire to the alternator. Somehow this circuit must have gone bad...:dunno:

I must be missing something here, it sounds like when you replaced the
PCM it solved your problem.

So, to cut a long story short: I replaced PCM, alternator, battery, and still have the problem with the voltage light! But charging and voltage levels are absolutely OK. Therefore I am almost certain the error lies in the instrument cluster. I removed the cluster and resoldered some ICs, and this helped for a short time.
I suspect an IC being bad on the cluster board, or the PCB itself has a faulty connection.
However here you are suggesting that the instrument board has a problem
.
In my case I have now re-checked all the connections and they are fine.
Just today I drove it about 100 miles during that time the light would
flicker on/off sometimes and stay on solid sometimes for maybe 10 miles
or so.
However all the time the gauge always showed either a slight charge
or vertical indication as it always has before this light on/off started.
I am just worried this light indication may mean that the alternator
is overcharging the battery and I may have to replace both alternator
and battery.
Thanks,

Think I have found the answer, at least in my case.

Its the gauge cluster, just not sure how to correct
the problem.
When I tap on gauge the red light can be made to
go on/off and even stay on continuresly.

Guess I will have to live with it since I have no idea
how to get to or fix this light, unless someone else
has already done this.

Thanks,

Gee you seem to have found the location of the problem.. Proubbly a connection near the guage.

Because the gauge cluster is all electrical, it is unlikely that the single voltage light problem can simply be repaired. Your best bet is to replace the cluster assembly, and doing that only takes a few minutes!

Because the gauge cluster is all electrical, it is unlikely that the single voltage light problem can simply be repaired. Your best bet is to replace the cluster assembly, and doing that only takes a few minutes!

Thanks, any suggestions on where I can find some good info on
doing the replacement for a newbee like me including purchase of
cluster. Hate to go back to dealer, there goes another thousand.

I looked for a shop manual but can't find one for my 94 other than
chiltons and that doesn't seem to have much info in that area.
Used to be there was a motor's manual but can't find that.

Thanks, any suggestions on where I can find some good info on
doing the replacement for a newbee like me including purchase of
cluster. Hate to go back to dealer, there goes another thousand.

I looked for a shop manual but can't find one for my 94 other than
chiltons and that doesn't seem to have much info in that area.
Used to be there was a motor's manual but can't find that.

Helm incorporated for the factory service manual.

http://www.helminc.com/helm/Result.asp?Style=&Mfg=GMC&Make=BUI&Model=PARK&Year=1994&Category=&Keyword=&Module=&mscsid=0DUPKAFGNF568MTU39M3A7HA9BF1430E

There's an ad on the page before I got to this one that GM manuals 1990-2000 are 50% off til Deccember 31.

Good find there imidazol97! I noticed that they are including the Electrical Systems Manual "free", with the purchase of the 3000 page service manual! WOW, can't beat that for 52 bucks anywhere! Helm Incorporated: Product (http://www.helminc.com/helm/product2.asp?class%5F2=BUI&mk=Buick&yr=1994&md=Park+Avenue%2FUltra&dt=&module=&from=result&Style=&Sku=94BUICKCH&itemtype=B&mscsid=0DUPKAFGNF568MTU39M3A7HA9BF1430E)

Helm incorporated for the factory service manual.

http://www.helminc.com/helm/Result.asp?Style=&Mfg=GMC&Make=BUI&Model=PARK&Year=1994&Category=&Keyword=&Module=&mscsid=0DUPKAFGNF568MTU39M3A7HA9BF1430E

There's an ad on the page before I got to this one that GM manuals 1990-2000 are 50% off til Deccember 31.

Yes, thanks for the suggestion, ordered one today.