INstrument panel Lights OUT....

everything is working (instrument / check lights...ac..vent), except for the dash lights / back lights for AC panel. Dimmer switch is not working, and at night time, I now have an excuse for speeding. when I turn my day lights on the lights come on.....But at night when I turn my headlights on the instrument panel goes off..........

I'm having the same problem...If I turn my lights on at night my dashboard panel goes dim..I can barely see