2003 GMC Sierra 1500 4x4 Mid-Bec

Ok wire people! lol Can someone tell me or show me the pinout for the Hdlnr 1 Brown 12 connector in the Mid-Bec? The dash and things were changed on this before my sister got it and the Third Brake light and Cargo Lite and interior Dome light and things dont work! They all go to a brown 12 way connector in the Drivers side fuse panel at end of dash but I believe it plugs into the mid-bec! Any help? I dont know if that plug is suppose to be in the fuse panel there or the Mid-Bec at the drivers left foot area! And if it does go in fuse panel why do only half the wires go to prongs (which there is only 4 prongs) and 8 wires and the only hot prong in that plug in fusebox NONE of them touch!! I dont know anybody??