I purchased a high mileage 2005 Chevy Suburban 1500 Z71 today that came with pretty much every available option on it... So far everything seems to work with one exception... I cannot get the DVD to play sound... Picture is fine, but nothing comes from the DVD...

I took the Rear Audio controls apart and cleaned the buttons because they were sticking, but that hasn't helped...

1. I can get the sound from Am/Fm/XM to work fine from the rear
2. When I choose source "DVD", the rear speakers go silent, no sound at all (front player show's "DVD" on screen)
3. I tried using wired headphones (no wireless came with it), they work fine for everything except the DVD, once again, no sound when that is selected...

Does anyone have a suggestion? Is there a fuse that controls the sound link? (Sounds crazy, but thought I'd ask) Is it possible there's a loose connection, and if so, where in the world might it be?

Any help would be greatly appreciated...