1996 Pontiac Grand Am Flickering dashlights(all or them)

Tiny
THOMASCRAWFORD
  • MEMBER
  • 1996 PONTIAC GRAND AM
Electrical problem
1996 Pontiac Grand Am 4 cyl Automatic 121000 miles

I am having an issue with my dashlights all flickering in my car. Every light will flicker while I am driving. I had the car tested and they pulled up a PCM overheat but said they are not completely sure that is the problem. I just paid $120 to have someone "half" look at it and I need an opinion from someone that doesnt charge an outstanding state wage to "look" at a car.
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Monday, April 19th, 2010 AT 11:55 AM

7 Replies

Tiny
CARADIODOC
  • EXPERT
Hi thomascrawford. Welcome to the forum. Beginning in 1987, GM went from the second best charging system to the worst pile in the world. It is very common to go through four to six of them in the life of the car. They are responsible for a lot of running problems even when they are still recharging the battery. A real fast test is to unplug the small connector from the generator. If the dash lights stop flickering, suspect a defective diode inside the generator. The generator can be repaired, but it is not possible to perform a test of the internal voltage regulator. It's also very difficult to get the stator wires separated from the diode assembly. It's just easier to replace the entire generator. Check around if it comes to that. My friend just put the third one in his Malibu, and he found one with a five year warranty at a much lower cost than one from a different store with a one year warranty.

Caradiodoc
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Monday, April 19th, 2010 AT 10:11 PM
Tiny
THOMASCRAWFORD
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Is the generator the same thing as a alternator and is the pretty much the best bet on the issue Im having?
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Tuesday, April 20th, 2010 AT 10:47 AM
Tiny
CARADIODOC
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Yup, they're the same thing. To be technically correct, (something I strived for as a former instructor), the term "alternator" was copyrighted by Chrysler and first used on their 1960 models. GM followed around 1964 and Ford a little later, but to avoid copyright infringement, they called them a "dc generator". "Alternator" is the commonly accepted term but now the industry is trying to standardize terminology among manufacturers and they've chosen "dc generator". To us older people, anything with "generator" in it leads us to think about the pre-1960, very heavy, bulky, inefficient generators of the past. There's WAY more than you wanted to know!

There are other things that can cause your dash lights to flicker, but the generator is a real common problem. Your car also is full of computers that are susceptible to voltage spikes and fluctuatons. A Body Computer is involved, and there is some computer circuitry in the instrument cluster itself. The easist way to narrow it down is to unplug the generator so the car just runs on the steady voltage from the battery. If the flickering stops, the generator is the most likely suspect.

Caradiodoc
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Tuesday, April 20th, 2010 AT 11:43 AM
Tiny
THOMASCRAWFORD
  • MEMBER
Okay, I had the alternator tested and its actually good. I am thinking it is something electrical. Car is currently not starting and lights flicker and also stay completely on. Head lights also flicker as well. Had another test done on it and it read PCM Overheat. Along with some buss thing as well. Hard to read the scribble when written by mechanic.
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Tuesday, April 20th, 2010 AT 12:02 PM
Tiny
CARADIODOC
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Go back and reread the original comment. It WILL test good but that only applies to recharging the battery. The problem with this design is it also produces voltage spikes and surges. Other manufacturer's generators don't do that, and it wouldn't normally cause a problem on older, simpler cars. Newer cars have a lot of computers that can't tolerate voltage fluctuations. Unplug the small connector on the side of the generator. If the flickering stops, replace the generator.

Caradiodoc
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Tuesday, April 20th, 2010 AT 1:50 PM
Tiny
THOMASCRAWFORD
  • MEMBER
Another issue I am having is Where is the PCM in a Grand Am GT?
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Tuesday, April 20th, 2010 AT 8:13 PM
Tiny
CARADIODOC
  • EXPERT
I'd rather have you ask me something I know the answer to. :)

If I remember correctly, I think it's to the right of the steering column on the firewall, (inside the car). I have one here someplace. It's silver, about 6" x 10" x 2". Can't remember how many connectors are on it.

Caradiodoc
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Tuesday, April 20th, 2010 AT 8:35 PM

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