Hi, new member here looking for a solution to a strange problem. I have a 2004 GMC Sierra SLT Duramax Crew Cab with the rear seat entertainment package (Ceiling mounted DVD and center console radio controls), all stock, nothing aftermarket. The other day the head unit and rear center console radio controls stopped working - blank display, no sound from any speaker, no "on-star ready" greeting and no door chimes. The DVD player however, still works except that sound will only come through the headphones. One interesting part is that I can hear what appears to be a faint humming/fan sound coming from the small speaker on the celiling above above my head on the driver's side - I guess it's the on-star speaker...

I checked the interior and engine compartment fuse blocks and no fuses are blown. I figure it's a shorted wire somewhere, but it's puzzling since the DVD still works. I'm guessing the DVD gets its power before the HU and the HU powers the rear radio. So I'm thinking I have to look for shorted wires from the engine bay fuse block all the way to the HU. I'm reasonably mechanically inclined and can probably do the work myself if not too involved, and I just need some idea as to what wires to look for (color, etc.), where they are routed in through the engine compartment, and possible wire pinch/kink points where a short could occur.

Thanks for the help!