My dashboard won't get illumination unless the dimmer light switch is all the way up at night. When i put the dimmer switch the in the low or middle position nothing is illuminated (Radio / A/C / DASHBOARD) except for On Star / Shifting Column. The dome light works. What may be the problem? Please help. Thanks

 

I going to have to say dimmer switch. I've never seen this before but it only makes sense. The sweeper brushes may be worn and not making contact with resistor inside dimmer switch. Kind of like what happens to the fuel level sender in the fuel tank. It's generally always the brushes that wear out and no longer make contact.