trailer wiring lights

I have tried to hook up the lights into the harness at the back from the 5 wire harness into the 4 prong plug at the other end. Using a test probe I have identified all the wires and went to town wiring evrything up. After testing with a test probe everything went well. As soon as I hook up the tailer the radio dies but the lights work. Any help? I use the diagram previously listed but still the radio dies. I switched the ground and brake light around and still the same problem.

bmp

Welcome to the form. check this link for the trailer light hookup. http://www.my-chevy-venture.com/trailer-wiring.html

or this site http://www.trailerwiring.com/