Tow Hitch Wiring
 

Just purchased a 2009 Aspen. It has the factory tow hitch and the blue connector near the parking brake for adding a brake controller. The round connector is totally missing next to the tow hitch. There is a loose set of wires for the flat 4 wire connector. I want to add and hook up the combo 7 wire round connector, along with the flat 4 wire connector but don't see where the wires coming from the dash are located under the rear bumper (including the blue wire for the brake controller). Anybody know where to locate those wires near the rear bumper? Thanks.