Aftermarket audio/video in 2006 H3
 

I have an H3 2006 with 5 aftermarket video screens. Recently, a battery was connected in reverse and I had to hardwire a new alternator to the battery because apparently my wiring from alternator to battery was burned out. Before and after the installation of the new alternator my audio in the truck was out, the receiver seems to be fine, lights up and can turn volume up, but no sound!:confused: I've checked fuses and everything else in the truck seems to be working fine! My auto dealer took at look at the truck with no solution! My truck has already been at the dealer for weeks with them looking at it:( Anyone have any knowledge regarding how to repair my Hummer's audio issue?