Originally Posted by pizzaguy

WHo knows what was done when the aftermarket head was put in. I'd pull the head and look at the wiring back there. BUT, it could also be that debris under the wipers has clogged the drains and rain water has backed up and ran down behind the mat and ruined the amp.

In any event, you DO NOT want one of those factory amps any more than you want an OEM head. The sound system is not hard to upgrade. A new JVC or KENWOOD amp can be had for under $100, under $200 if you are demanding of a lot of power (which hte factory speakers barely can handle).

It would not be hard to buy an amp and new head and start over. My JVC head was $85 at Best Buy and it sounds WONDERFUL. I run mine without an ampl, my car is a Base with no rear speakers or amp.
I changed the head to hte JVC head, added rear speakers, and was happy for under $200 and about three hours of my time.

That's how Id do it, just start over. But seriously, pull the mat up and check for water under there. Don't let that go.