Nope it is just a factory delco system (gm brand). I've pretty much narrowed it down to a wiring problem with the speakers because 2 of the speakers (one in back seat, one in trunk) haven't worked since i got the car and one of them (other side back seat) was very quiet. I bought 6 new speakers today to replace everything and the one in the back seat that didnt work still doesnt work even with a new speaker, and the other is still quiet. I'm guessing the amplifier in the head is shutting off because of a short.

Anybody have any ideas on where I should look first for faulty wiring, or some sort of tool that measures how much is going through a wire?