Good evening Hummer Forum
I have owned 3 Hummer H3’s and have loved them all. I currently own a 2009 white luxury model.
It has 10200.00 miles and is still running strong. I recently replaced the side panel on the drives seat as it was loose and constantly hitting the power seat heater button and turning it on. Problem found, the factory never installed all of the clips to hold it in place.. But I fixed it and it works great now..
Recently, however, my interior lights (A/C, door switch’s and headlight buttons) go out when the brake pedal is press and / or the vehicle is placed in drive. It doesn’t happen all of the time, but enough to make me mad... I noticed the other day (they were all out), when I drove into the garage the running lights (fog lights) came on and so did the A/C , door switches and headlight buttons..Can’t figure it out, if anyone has any ideas, it would help me out a lot. I changed all of the bulbs, as-some of them had burnt out, but it’s still acting up. When I press the brake, I can hear a click with the lights go out.. Confused.

 

Wow,only 10k miles. Sit back, Doc will be with you soon.

 

I believe the issue is related to the running lights. When it is somewhat dark ( like real cloudy or in the garage), I will start the vehicle, depress the brake or place it in gear, they stay on 95% of the time. When it’s bright out and the running lights are off, when I turn on the vehicle, and or place it in gear, the interior AC lights go out.

 

Have you read the owner's manual for your truck yet???? It's a thought.

 

I don’t have a owners manual, how ever I don’t think it would have the information I need in it.
I start the vehicle and all lights are on inside the vehicle including the AC (3 *****) lights. But sometimes when I step on the brake and shift the vehicle the 3 AC lights, window switch and the lights on the dash for the headlight/ running lights go out .it does not happen all of the time. However, I did notice ( when running lights were not on) and I pulled into the garage, the running lights came on and so did the AC lights, window switch and dash lights for the head lights. Confused..

 

There is an ambient light sensor on the top off your dash; looks like a little dome. That controls when your headlights (and interior dash/switch lights) come on. That's why the lights came on when you drove into the garage.

As for hitting the brakes and/or putting it in drive... That's also normal; they don't come on if you are in park, only when you shift into drive, AND only if it's dark enough outside.

Make sure there's nothing on top of the dash blocking the sensor.

 

Thank you for the reply. Nothing in front or on the dome sensor. Should that affect the A/C lights ***** also?.
I think maybe if I change the headlight switch, it might correct the issue, what do you think?
I noticed the other day when parked in the garage, all lights were working properly, Fog lights, daylight running, A/C **** lights, until I pulled out of the garage completely, then that all went out.
its not a big problem, but it’s nice to have the vehicle with all things operational..

 

Owners manuals direct from GM.
FREE DOWNLOAD
https://my.gm.com/how-to-support/manuals

 

The lights (both exterior and interior instrumentation) WILL be on when you are in the garage, since it is relatively dark. Once you leave the garage (in the daylight), all of those lights will turn off (and DRLs will turn on) automatically. Manually turning the lights on/off will override that, but only until you turn off the vehicle and restart it. Unless I'm not understanding your issue, I'm not convinced that your H3 is doing anything that it isn't supposed to be doing. When it is light outside, only the DRLs will be on. When it is relatively dark outside (or in a garage), DRLs will turn off and the interior illumination, headlights, & taillights come on. It takes a few seconds to react; it isn't instantaneous (otherwise your lights would be flashing every time you drove under an overpass).

 

Thank you, but that doesn’t explain the AC **** lights going out, along with the headlight switch and window switch light. They go out and come on too.