Pulsating headlights and interior lights

Kurt K

SCCoA Member
I've been driving my 95 SC for about 2 weeks after sitting for quite a while. Anyway, tonight was the first time driving at night and I noticed that the headlights would slightly dim and brighten repeatedly...the interior lights were doing the same.

Any suggestions of what the problem is? It's been suggested that it could be my ignition switch, but I'm looking for confirmation or other suggestions.

Thanks

Edit: I found these three posts, a couple without solutions.
http://www.sccoa.com/forums/showthread.php?t=77371&highlight=Pulsing+headlights
http://www.sccoa.com/forums/showthread.php?t=47796&highlight=Pulsing+headlights
http://www.sccoa.com/forums/showthread.php?t=48253&highlight=Pulsating+headlights
 
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It's been my experience that pulsating lights are due to poor body-to-battery grounds.

Easy to check with a meter. Negative probe on the neg terminal and positive probe on some bare metal on the body with the problem occurring. Anything over about .2, and preferably .1, needs some attention.

You might also check from the engine to the battery negative while you're at it. Same story otherwise.
 
I'll do that when I get a chance.

I do have a little bit of followup. This morning when I drove the car to work, none of the lights were pulsating when I started the car this morning or for the first couple of miles. But when I arrived at work, the pulsing was back.

Could the increased heat of the engine compartment add to part of the problem--alternator or battery getting hot?
 
A poor electrical connection will build up heat at the connection, which will worsen the connection (resistance goes up with temp). As the circuit operates, the resistance will worsen.

Nick
 
Kurt K said:
Anyway, tonight was the first time driving at night and I noticed that the headlights would slightly dim and brighten repeatedly...the interior lights were doing the same.

That's the rare 1995 only Disco Lighting option that was offered on our cars. Man, I really wanted that option when I bought mine. It was the one option mine didn't come up. You're so lucky, Kurt.
 
Same Problem

Kurt K, I have the same problem with my 95 SC. I replaced the alternator about a week ago. I checked the battery before the swap and it checked out. My wife has been driving the SC daily, and then complained about the headlights and interiror lights pulsating. I have no idea what this could be. If you find a fix let me know.
 
well, let me be the next one to jump in... mine does it too... but it'll die sometimes too, and the alt does get well above 200*... i think its time for another.... and i'll check all the grounds.
 
I don't know if this applies to your year Bird, but my 93 had a lighting recall.
The driving lights would pull to much current for things as they came from the factory. The headlights would not pulsate--but would flash off and on.:eek:
 
I just went through something similar. Before my alt cut out alltogether, I had times where the lights would suddenly brighten :confused: and on some occasions would oscillate a bit.
 
Sorry I never posted a follow-up. I ended up replacing the alternator (after the original one finally left me stranded) with a oem replacement. Everythign has been fine since.
 
My wife's Oldsmobile Intrigue sometimes does the same thing in cold weather. Apparently, the problem shows up a lot in those models. They traced it to a faulty voltage regulator in the GM alternators that malfunctions in cold weather. GM released a fixed alternator, but since it is $300-ish, I have let it slide for now. Anyway, I just thought that I would chip in a little additional info.
 
Kurt K, I have the same problem with my 95 SC. I replaced the alternator about a week ago. I checked the battery before the swap and it checked out. My wife has been driving the SC daily, and then complained about the headlights and interiror lights pulsating. I have no idea what this could be. If you find a fix let me know.

As I think someone else might have mentioned. If the battery and alternator are both good, then you need to check the battery cables on both ends. Not only the connections, but the cables themselves.
 
Had the same issue on my 91 (but as the posted above, they would go off and on when I ran the highbeams for too long). The problem was too much current through the main switch (this was when I ran papers, with the hazards, headlamps and brake lamps on alot, all of them running through the same switch).

What I did: ran relays for the headlamps, which got about half the draw away from the switch. It's not all that hard to wire either.
 
Had the same issue on my 91 (but as the posted above, they would go off and on when I ran the highbeams for too long). The problem was too much current through the main switch (this was when I ran papers, with the hazards, headlamps and brake lamps on alot, all of them running through the same switch).

What I did: ran relays for the headlamps, which got about half the draw away from the switch. It's not all that hard to wire either.

It might help someone else, but my headlights already have relays :)
 
last winter i was having issues with my headlights -they would start flashing ,i figured it was the headlight switch overheating ,i bought another h-switch but have yet to install

should i re-wire the harness for the lights or should i go the relay route
has'nt been an issue during this summer

steve
 
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