URGENT: Help with Radio Install

[My Wife\'s Hummer]

I got it!!! Thanks to everyone on this board that has commented on this post and others involving head unit installs. I figured all of it out from this board.

The purple wires was the trick. I had held out on hooking them up because i wasn't sure if I was ready to install everything. All I have left to do is install the rear back up camera. Still not sure on how to enter the wiring into the cab. I tried a post but not too many responses. Anyone got some ideas?

thanks