hey im having some issues with my audio in my 02 TRAILBLAZER. The front right speaker has only treble, and the right rear speaker has nothing at all. I took my truck to the local chevy dealer and they told me i needed a new radio, no big deal. Got a new radio but still have the same problem. The guys at ABC (where my new radio came from) told me that the radio was never an issue, but rather a factory amp somewhere in the truck, which the dealer didnt mention at all. So my question to any who know is, where is the factory amp located if at all there, or has anyone else had the same issue and how did you solved it? Only having half my speakers is driving me nuts!!!!!