Newbie question (I hope)...previous owner of my 1992 T/A had replaced the stock radio with a late 90s Pontiac cassette deck, but gave me the stock radio. The lighting on his replacement worked fine. When I put the stock unit back in, everything works great, except there is absolutely no illumination on the unit EXCEPT for the cassette deck and clock. It could be the bulbs are burned out, but it seems weird that they would all be out except for the cassette module.

Any ideas?

 

So my problem has gotten weirder yet. I pulled the unit apart and it doesn't appear any of the bulbs are burned out. When I put it back together, a different bulb is illuminated while the one that was on is now off. If I give the unit a hard tap, sometimes one additional bulb will come back on. I figure it has to be some sort of a connection inside the radio, but I completely disassembled it and don't see a problem. Any ideas?