I noticed while driving tonight, that my dash lights were flickering, ever so subtley. Then, I watched my headlights on the car ahead, and they also were flickering at the same rate. So then, ALL my night lights are flickering, rapidly, but just slightly.

I am thinking it is probably a bad ground wire. Where should I look? What else should I look for? Thanks!

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FORMULA 350 TK
Southern California 3rd Generation F-Body OrganizationŠ

 

Were they flickering on and off or where they diming and getting brighter? If they were flickering on and off it sounds like a bad ground or loose wire somewhere. In the f-body's there were a lot of wires for lights so I'm not sure where to start. You'll need a wiring diagram out of a chiltons or something. Now if they were getting brighter then dimmer you may not have enough power. Especially if you have a big stereo system. If so watch to see if it happens with the radio off and if the dimming goes with the music. If not watch you volt/amp meter if you have one and see if it moves up and down with the dimming. If any of this happens you might need an altenator with more amp output.

 

Sounds like your alternator might be dying..

 

What exactly do you mean by "flickering?" If the lights are getting too bright and then too dim and so on...and if the voltmeter is fluctuating too...I would suspect a bad voltage regulator. The regulator is built into the alternator on GM cars, so this would mean replacing/rebuilding the entire alternator.

I once had a car with a bad regulator...the alternator was charging at such a high voltage that it took the battery out too. I would look into this before you have battery problems.

 

Yes, to clarify they are getting dimmer/brighter/dimmer. Rapidly, but just slightly different in level of brightness, but certainly enough to catch my atention. I had the alternator rebuilt several months ago. I think the idea of a bad voltage regulator might be a good lead. I just had a dead battery the other day, due to a loose battery terminal. Maybe the regulator got over stressed because of it.

As for wiring diagrams, I have them. What I meant by "what to look for" was for example the idea of a dead regulator, etc that you guys posted. Thanks!

 

Tom,

Just FYI.
Had the exact same flickering in my 88 GTA. It went away after I started disconnecting stuff to track down a fuse-blowing problem The fuses are still blowing, but the flickering has gone away, with the fuses in and with them out . I have been disconnecting stuff in the accessories fuse circuit.

Hope you have already solved your problem.

John

 

I have the same problem. Please see the Topic: (electrical problems 98 Firebird V6)for details. Did you find out what was causing the problem. If so, please tell how to fix the problem.
jlc

 

sound like the diodes in the alternator are going bad have alternater checked for AC ripple

 

UPDATE:

I loosened, and retightened the nut on the passenger side ground strap from the firewall to the cylinder head. The flickering seems to have stopped for the time being.

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FORMULA 350 TK
Southern California 3rd Generation F-Body OrganizationŠ

 

Good to hear you had an easy solve on that one Tom, wish they were all that simple! I've got a blown diode on my daytime running lights('92 C1500 E/C), that I've got to find and replace tomorrow. Then I've got to trace a bad ground on dashlights(83 S15 Jimmy w/'88 LB9). And if I have any energy left,... replace a bad HVAC panel that intermittently shorts(only when the vehicle is running) which draws most of the available current('88 IROC). Thank God for the spagetti diagrams in the back of Haynes manuals(lord knows they ain't much good for anything else). Kinda makes me wonder when GM/Delco started hiring EE's from the "Prince of Darkness"(Lucas Electrics)?

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He who hesitates,... is lost!

 

88IROCs:

You must be an old fart like me if you know about the Prince of Darkness!

I learned about that rat bastard back in the late 60's!