When I turn my suburban on with the headlights on, the backlighting of the instrument panel and the console stay on for a few seconds and then turn off. My dome lights don't work, nothing. I turn the dimmer switch all the way up. It changes my information center and the individual lights, but my backlight stays off. The only way to turn on the dome lighting is to turn the dimmer all the way up. Cant figure out where to start. I checked fuse 7 "instrument panel back lighting" and it was fine.