wiring diagram for factory 04 gm overhead

installing into a 2002 chevy duramax dually. the only info. ive seen on it is it was made in 2004 by GM. ive got the actual overhead console with the flip down and a display screen  right before it ,and then the dvd head unit is seperate i guess because its mounted in the dash. i need to get it to working by just putting power to it and a couple of speakers that way i could mount it however i came to figure out. i figured being i  had all the pieces there has to be away to just supply power and speaker and it come alive(i hope)