Black89-6spd

My dash and all exterior lights on my '89 flicker or pulsate. What causes this and how can I fix this?

JCAIRE2

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:

Grzldvt

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.

jfb

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.

Ray Quayle

jfb, I just love when you talk technical! :D I've been gone for a while and it's great to see you are still here.

johnno!

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:

RadPolo96

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.

Black89-6spd

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.

jmrl98

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

vettmech

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.

Steel Blue 91

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.

scorp508

Check your alternator as suggested, it could be on its way out. Mine did this before.