I just replaced the rear bumper on my '03 2500 HD Duramax. The plug that connects at the rear under the bed had the wires disconnected from it. I need a diagram to figure out what wire goes where. The plug had been disconnected from it for some time, and the socket that it plugs into was filled with crud, but has since been cleaned out. What fuse looks after this circuit? How do I test for power at the socket? I've tried the test light, but I don't know which pin is hot and which is ground. Thanks in advance, Ric.:help: