If your car has the amp, it will ba a black box under the passenger seat. You can see it by moving the passenger seat forward and looking in from the rear seat.
The wiring for it goes in in the front, which makes me think that someone may have shoved something under the seat from the front and knocked a wire loose there. Move the seat all the way back and use a flashlight to check the connections there.
Any answers on this? I have an 07 LGT, my radio displays perfectly as if its working, switches between radio stations, climate control works, turns on and off, but I get absolutely no SOUND! I have an OEM sub as well. Any ideas?