At ONBF last weekend, we started our cars to warm up before leaving. It idled for about 10 mins then my headlights went out, leaving only the fog lights on. We all thought it was funny, so I turned on the headlights manually - nothing. Then I put the car in gear - whala, lights came on. So we all thought that perhaps it was a build in function to prevent the headlights from wearing out.

Tonight...drove the car for 4 mins and parked in a driveway. Was there less than a minute and the headlights went off ...then on...off and on in a random non-pattern... sort of like there'* a short. Drove home (two minutes) with no problems while car was in gear.

Park in the garage, opened the door before shutting off the car (not sure why, just did it for some reason), shut off car and pull out the key. The "dinger" goes off like it does when you either 1) have the lights turned on manually with the car off or 2) when you leave the keys in the ignition with the door open and car off

Had to put the key in, turn to Access, then off again to make the dinging stop.

So... seems to me I've got a problem. Where should I look first? Would an old battery have an affect on the lights like this? (still have stock battery - 6.5 yrs old). I do recall this happening last year one time as well.

The headlights are controlled via the DIM (Dash Intergration Module) which activates the HDLP LO BM relay. The DIM is under the dash on the right hand side. Check all the connnections to the DIM, and the relay, which I believe is in the underhood fuse box.

With the serial data system that is used, a weak battery could cause strange problems, but I would expect there to be other symtoms, also.

Archon:
Sounds like the best place to start. A dirty or loose connection could cause this problem.

Tracy:
This is typical of an open problem not a short. If there was a short one of fuses should blow and need replacing.

I'd probably start by replacing the battery. It may not be the most likely suspect but I wouldn't try going through a WNY winter with a 6 1/2 year old battery.

Will do! Thanks guys!

Just jumping in here.
Have you checke the voltage on your battery, starting, idling, under loads?

I'd vote with replacing the battery now because you know it'* gonna give a problem. Save yourself the aggravation. I'd replace before troubleshooting. May be a cable, conection, or battery problem.

Also what are all these abbreviations?
ONBF
HDLP
DIM
LO
BM?

Yes....I've known that I need to replace the battery before winter... putting off the inevitable since it'* the side vented ones (aka more expensive )

ONBF = Ontario/Niagara Bonnie Fest
DIM = Dash Intergration Module
HDLP LO BM - I thought it was HeadLamp Lo Beam - but that'* just my guess

Alright, just to reiterate what Archon has already stated. The DIM is the central unit here. There are three conditions that will turn on the lo beam headlamps. 1) the headlight switch, 2) the twilight sentinel sw. turned on invoking automatic light control (sunload sensor input from HVAC module to DIM via serial bus link.), 3) the windshield wipers on at day time conditions. All three of these items input to the Dash Integration Module (DIM) to set conditions for headlights being on or off. The DIM has 3 connectors on it (C1, C2, C3), check those connectors secured. I don't minimize the fact that the battery is aged, and wouldn't be a bad idea to replace, but I don't think the battery has an affect on this problem. The car was running when this occurred, so battery voltage would be up around 14 vdc. This is a hard one to diagnose. Can't really establish a link between transmission being in or out of gear & head light control. DRL relies on gear selection. Tracy, this anomaly has never occurred while driving, correct? I'm inclined to think some malfunction with the DIM would be causing this problem. The DIM does control the HDLP LO BM relay by switching relay coil ground in or out. Look for any damp or wetness in the area of the DIM & its 3 connectors also. That'* my .03.

When funny things start happening, look at battery voltage- connections, battery age, quality...

or grounds...

Do 00+ Bonnies have grounds susceptible to moisture next to passenger seat and driver seat? in the left and right pillars next to driver and passenger feet?

That is correct.