I just recently bought a used 2005 GMC Envoy not equipped with the bose premium sound system. Im leaving on a 14 hour trip in IL in two days and would love to have my powered sub hooked up for the ride. I believe i have everything figured out i just need to gain access to the back of the head unit where the wires are. There doesnt seem to be any screws or anything to take it off. please help =]