This morning I started my car for work. The dumb daytime running lights kicked on normally, but they all of the sudden started flashing on and off rapidly. The interior lights were doing the same thing.

Can think of 3 reasons for this. Is it just when in the daylight? If so it is the Lighting Control Module that switches from DRL'* to low beam is shot. If it happens day or night then, have you switched lamps to a higher amperage. #3 scenario would be a loose ground.

Headlamps are the normal amperage. I have only witnessed the flashing during the daytime - not really bright, not really dark. Dawn timeframe when it can't make up its mind. I did turn on the headlights and it quit immediately. I have a GM warranty. I wonder if they will replace it, or will need to duplicate it? It has only done it twice now.

Mine did the same thing once. It stored a code but the dealer wouldnt do anything because they couldnt duplicate the problem.

I was worried about the dealer being able to duplicate the issue as well. I have a 150kb video from my cell phone, but I don't know how to attach it since it isn't a picture file. Recommendations?

A few more details. The interior dash lights, climate control, and stereo lights blink, but not the interior courtesy lights. The rear taillights, license plate light and side marker lights blink along with those on the front except the fog lights. Here'* the wierd part - if I reach in and press the fog light button, all flashing stops and all lights are on. If I turn the fog lights back off, everything starts flashing again. If I turn the headlights on, all flashing stops. If I turn the headlights back off, everything stays off and doesn't do it again until the next morning.

By turning the fog lamps on you are turning the lights on manually and overiding the automatic function. To me it sounds like there is an issue with the light sensor. If you are able to reproduce the problem every morning I would leave it at the dealer over night and then show them the problem in person. Then they will have to do something.

Rye Guy - Thank you for the info. I may have to end up changing it in the future.

Let me tell you what I have found out. On the end of my garage, I have two halogen motion activated flood lights. I walk underneath them in the morning to start the car. They slowly start to get brighter and brighter. Apparently this confuses the light sensor. If I shut off the garage flood lights, the car lights behave normally. This is 1000 watts of light kicking on in a pretty short time.

Bet GM didn't simulate THAT in their design process!

After having the car into the dealer several times for other repairs (new intake, idle air control valve, twilight sentinel) and complaining about it each time, they finally put a tech on it they have hired from Pontiac. I showed him my video and he immediately pointed out that it was key that both the headlights and parking lights were flashing because they are on different circuits. He said he found codes B2556 and B2641. The proposed fix is an instrument panel dimmer which is also referred to as a fog lamp switch on my service invoice. Part # 25762644. I will keep you posted.

Any update on the flashing issue? I have the same thing going on with my GXP!