Headlights Dimming...

[DjDuncman]

I tried searching around, but couldn't find anything that seemed to specifically pertain to my problem. I recently noticed that, when my car is running (esp. with the stereo on, it's completely stock, no amps) my headlights dim slightly when I press the brake. Just about 4-5 days ago I installed new sparkplug wires and a new alternator, b/c the old alt. sounded like a bearing or something was going bad. Before changing the alt. I checked my batt. voltage to make sure the old alt. was charging and with the engine off the batt. read 12.8 volts, running was 14.5 or so. I'm getting the same readings with the new alt. but now the headlights dim. (I'm not completely sure if I just didn't notice this with the old alt. or not) So I was wondering what the possible problems might be. the car is an 02' with the original batt. in it. I was thinking maybe possible bad/dirty grounds or the, supposedly stock alt., is putting out fewer amps but I'm not sure. This happens with either low or high beams, and is more noticable with the high beams (obviously) Also, the lights don't seem to dim at all while the engine isn't running. Any info. is much appreciated. Thanks.

DD

PS: The new Alt. is a Duralast Gold, the only Alt. they had at the nearby Auto Zone.

[jditch1979]

clean the wires at the battery and then check the lights if dimming still it going on the battery is shit. I just replaced my battery on my 02. Go with a red top battery there the shit!

[GrandAmSSE]

Battery. The alt can help the battery cause its not charge right and when you turn stuff on or use the brake lights it sucks more power then you have and it dims.

[RedGrandAm2003]

Yeah I have that problem too. I tape the brakes, put up the windows, etc, and that happens. Had the batt and alt tested, and everything is fine. Mechanic said it was the alt. My alt has a loose wire or something because it seems to die occassionally, so I'm gonna bring my alt to someone to fix it for me, but I might get a batt sometime. Donno where to get a red top battery though, oh well... havnt really looked.

[dmbprep69]

Yeah throw a redtop in there! I had the same problem b4 as well.
Peace,
Andrew

[Tebore]

There's a chance that the new alt just isn't as good as your old one. Some cheap alts just don't have much windings, and a strong a set of magnets.

Or it could be that the alt was designed to be a lower drag unit meaning it produces less power but it takes less engine hp. The shop I went to replaced mine with one of those(I didn't ask for it just what they had at the time), when I got the car back I noticed it reved faster but when I hit the brakes the lights dimmed.

[DjDuncman]

Thanks to everyone that responded. I guess I'll just go with the probable "bad battery" since it's the most popular response. But supposing it is the alt., can I put a slightly smaller pully on it (assuming I can find one) to increase the rpm's a little and get that extra power back? ehh, whatever, 4 years is prob. a good time to replace the battery anyway, even if it is working fine. Thanks again everyone.

[RedGrandAm2003]

well everyone has reported the headlights dimming since they bought the GA. I know it has been happening to me. Its no biggie, just annoying. Cuz it happens with the windows going up/down too. But yeah, just replace the battery and it should go away is what i kept being told.

[themoo2112]

I had the exact same problem with mine. Id step on the brake or put the windows up and the lights would dim. Unfortunatly I waited to long to get it fixed and one day I got gas, hopped in and nothing worked! Got it towed across the street and threw in a new battery. The only weird thing was that battery that was in it was only about 10 months old. The did a load test on the thing and said it was dead. So I took the old battery back to Napa, they tested it, said it had a full charge on it!Weird!!

[RedGrandAm2003]

I actually brought my car in and had it tested.... the alternator was putting out power, it was working A+. Batt was taking the charge, wasnt dead, was perfect.... My car dies and I'm confused weather to replace the alt, batt, or car. lol

[Matt95GT]

At idle, it's completely normal to have a slight dim when you press the brake pedal.

[RocketFast321]

I just know in the winter time our 97 malibu dims like a mother when it's cold.