I had the same type of issue with my 03' and it turned out to be some type of resister or something located under the glove box up against the fire wall. I could hear it clicking when it wouldn't come on and also smelt burnt wire as it got worse. Turns out the wires were fine but the unit was screwed (can't remember the name of it). May give you a place to start. It's not very big, maybe the size of a "D" battery.
