Flickering dash and headlights
Le Mans Master
Joined: Jun 2002
Posts: 6,097
Likes: 0
From: High Plains Drifter Fayetteville, AR
Re: Flickering dash and headlights (Black89-6spd)
Kinda sounds like a ground problem. I'm not electrical expert though, so someone else will probably be able to help you more. Welcome to the forum.
J :seeya :steering: :steering:
J :seeya :steering: :steering:
Safety Car
Joined: Aug 1999
Posts: 3,750
Likes: 1
From: San Jose CA
Re: Flickering dash and headlights (Black89-6spd)
Mine did that, and it was the alternator. I was putting out a very high 14+volts to a low 15. Located a ton of posts that discussed this subject and a vast majority pointed to a bad alternator. What does the gauge say?
You can always take it off and bring it to your local auto parts store, 90% of them will test it, some while it is still on the car.
You can always take it off and bring it to your local auto parts store, 90% of them will test it, some while it is still on the car.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: Flickering dash and headlights (Black89-6spd)
First, remove both battery cables (neg first) and clean the cable lugs and the battery posts and replace (neg last). If it is still doing it and the flickering appears to be constant (not random), I would suspect the voltage regulator in the alternator is oscillating. If you want to take the alternator apart, you can replace the regulator, otherwise replace the alternator. Proof that it is oscillating can be done by looking at the waveform across the battery with an oscilloscope. There is normally half sine pulses of a very small amplitude from the alternator, but if it is oscillating, the waveform will be sinusoidal.
- 1986 Original Owner -
Joined: Apr 1999
Posts: 3,193
Likes: 139
From: North Yorkshire, England
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Re: Flickering dash and headlights (jfb)
amplitude oscillating sinusoidal waveform oscilloscope
Racer
Joined: Dec 2002
Posts: 498
Likes: 0
From: Utica NY
Re: Flickering dash and headlights (Black89-6spd)
My trans am did exactly the same thing, it was a bad engine ground near the rear f the engine/intake manifold. try to clean the battery first, then check for bad grounds. Good luck
John :cheers:
John :cheers:
Drifting
Joined: Oct 2001
Posts: 1,759
Likes: 0
From: Round Rock,Austin, Texas
Re: Flickering dash and headlights (Black89-6spd)
I have the same problem as well, but it usually happens the most when I hit the brakes or something like that...I will see the dash dim slightly and the headlights as well.
Thread Starter
Advanced
Joined: Jan 2003
Posts: 80
Likes: 0
From: Freeport Illinois
Re: Flickering dash and headlights (Grzldvt)
I took the car out to day and the lights weren't flickering. The volts were at 14.5 to 14.6 most of the time. I bought this car at a dealership but I got a hold of the previous owner who says he only had about 1500 miles on the new alternator. Since then I've only put on about 2000 miles so I wouldn't think it is the altternator.
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Drifting
Joined: May 2002
Posts: 1,509
Likes: 3
From: Hazel Park MI
Re: Flickering dash and headlights (Black89-6spd)
Check the battery - my dash lights cut out as well as rough idle during the episodes, which turned out to be the battery. We have to watch it up here in the more temperate areas - the extreme change in temps is a mother scratcher! :yesnod: :seeya
Drifting
Joined: Feb 2000
Posts: 1,994
Likes: 0
From: Charleston, WV
Re: Flickering dash and headlights (jmrl98)
Battery problems can really mess with ya. How old is it? If it's time, according to years, then maybe it's time. I would also check the ground on the belhousing. If this sucker is loose it will shut the dash off completely. It's on the left side of the belhousing and the second bolt up. It's not the easiest to reach with a wrench so it gets neglected often. Make sure all the wires are tight on the alternator.
Le Mans Master
Joined: Jul 2002
Posts: 5,818
Likes: 2
From: Alive and well in Burlington NC
Re: Flickering dash and headlights (jfb)
Had the same issue. Check the terminals as suggested. My problem turned out to be a cracked lug. As soon as I started to remove the negative lug to clean it, it fell apart! It had been over torqued at some point.
