OZ757

Greetings all,
New member here looking for some help. First, let me say I have searched through the past threads looking for an answer. The ones i have found have not solved my problem.
My 2001 (2002 model year) Avalanche instrument cluster backlights do not come on when the headlights automatically (or manually) come on. The info center alerts still work (such as Low Wiper Fluid), the odometer/gear indicator remain illuminated and all alerts (seat belt, High beam, etc.) still work. However, the backlights for the cluster and the radio display all go out.
Thus far:
I have checked all in dash and under hood fuses.
I have checked the dash light sensor (cover it and the lights switch, uncover they switch back).
The headlight/dimmer switch seems to work (headlights come on manually and dome lights come on with the dimmer on full).
Daylight running lights come on normally and they switch to headlights/parking lamps normally (auto and manually).

I suspect it is a relay that changes the power to the cluster when the lights come on but I don't know which relay it is. I hear a click (from the dash fuse block) when the dash sensor is covered but I cannot identify the culpret.

Thanks for the assistance.

oldchevy

My 99 Silverado was doing that and it was the dimmer for the backlights that was the cause. I would just move it back and forth a few times and they would work until the next time.

OZ757

Oldchevy, Thanks, the dimmer appears to be working in that it turns on the dome lights when it's on full. I'll see if I can check it with a multimeter.

speedOhead

have replaced many of the dimmer switches on gm vehicles. most of the time the dome lights will still come on. the rheostat has gone bad. sometimes you can test this by turning the dimmer switch up as if you were turning on the dome lights, right when you feel the little click to let you know that the dome lights are coming on, wiggle the roller a little bit. sometimes you can see the clusters back lights flicker just a bit.

OZ757

Thanks for the advice Oldchevy and speedOhead, I ended up testing the rheostat Monday and, indeed, it was faulty. $105 later, I have a new switch cluster and everything is working.

speedOhead

awesome