Happens with both Kersh. When the car first starts in this weather, you figure the DRL'* are on, you have your heater blower going, and the air ride compressor kicks on.

The compressor activating makes a lot of sense. It'* not really loud enough to hear over the road and engine noise, so you wouldn't really catch it as being the cause. It must be a high enough draw that the alternator simply can't immediately compensate.

I owned 2 2002 V6 bonnevilles. I never had the issue with the dimming of lights, or a load on the electrical system. I suspect its common with the V8.

The issue appears to be getting worse. It'* happening more often. Condition: Within 2 minutes of driving away from a cold start, the front headlights dim. The last time it was noticed with the interior lights too. There is no way the fan is kicking on (32 degrees) and the heater is set to auto (little or no blower motor speed). Maybe it is the battery as the manager at GM suggested. I'll probably get one soon and report if there'* a difference.

This happened to me last night and I have been watching for it since reading the first post. I had started the car let it run while bringing the dog out. I left and traveled about 10 minutes and entered a on ramp for the highway when they went dim for as fast as you can snap you fingers. It startled me because it was just after letting go of the brake before merging into the slow lane. I thought the car had died.

For most of us, its just a glitch. Welcome to the Club J/B

I just put in a new battery as mine was 5 years old and thought it was time. The new battery makes no difference. This is just a quirk that you have to learn to live with.

Miy 05 GXP has done the same thing for the past 3 years, no reason or exact pattern, usually with-in first mile of driving, can't figure the variables to force recurrence. GM is as helpful with this as they've been with the steering thunk, can't get no satisfaction there either!. The dimming still mystifies me though!!

As for the battery as part of the dimming, its electrical and its gotta be all connected!, I have had 2 instances in the history of the car that for absolutley no reason it was dead in the morning. I mean, no interior lights, no remote, no nothing; completley dead. Jump started and monitored, all was well. Started looking for batteries (see thread) but never got one. Happened a second time and I was ready to buy but a local auto parts associate talked me out of it as my battery, though OEM should not need replaced yet. Guess what? Through the bitter cold of this past teo snowy winters, no issue with battery. When ready to go shop for a Class 100 battery only! No substitutes for venting when my family is at stake.

I have a 2001 bonneville, my lights dim driving down the road for about a second or 2 then it quits it never really bothered me but if theres a fix for it i would enjoy hearing it,i dont think its my battery because its almost new,its probly just a connection because ive noticed mine doing it say after a large bump or pothole

I've had the same think since new, and now almost 100,000 miles. Battery was replaced under warranty about 2007. No difference. Definite voltage drop. About 1 second, maybe less. There'* been a few threads on this already.
It has to be a fairly large start-up draw. I like the autolevel compressor idea. I had also heard it could be an air pump for the emmisions/cat converters. I have a similar Vdrop on my Camaro sometimes.
It seems to happen most consistantly within the first 1-2 minutes of start-up. Random after that.
I'm convinced we don't notice it most of the time, unless it'* dark outside.