Originally Posted by Elcamino man
I would take the head unit out, get at the gm07 wiring harness and hook up the remote power on from the aftermarket head unit to the remote power on, on the harness and see if you get sound. If you have the monsoon amp, all you need to do is power it up. And i would use the factory amp. it does all the processing for the factory system. Untill you get a new system, speakers, amps and the like.
I am fairly certain there is no factory power amp in the car unless it is under the dash. I have had the back seats out, trunk torn apart and from what it sound like if the ribbon run to the factory amp and then converts to speaker wire then the only place an amp can be in in the dash but know one has said the is the case. There are no ribbons running back under the back seat nor into the trunk that I can tell.
I am going to pull the head unit and connect it to an external speaker to double check the unit is not stuck in some kind of ATT mode. I know I should have check this already but figured new is new.