Towing Issues: 7 pin trailer hookup, chevy silverado 2500 hd, digital volt meter

Question
I have a 2001 chevy silverado 2500 hd. I just bought it about a month ago and need to go from 7 pin to 5 flat. I have the converter to go to 5 flat. I have a test light and when I check the plug it did not work, I would scratch around the plug and get it to work but it would only stay on for about 10 seconds and then would go out. I would cross the terminals and get alittle spark and then it would work for 10 sec and then go out. I unplugged the harness and tried second plug in , same result. I then wired the ground of the plug to a good ground , same result. the electric brake has not worked from the get go, but do not need it I am only hauling boat, can I bypass plug and straightwire 5 flat pin plug?? Thanks

Answer
You didn't say which wire you were testing and if you had a complete hookup while testing. Are you testing the brake feed? You stated the E brake has not worked, is it the control box or the brakes on the trailer? I would use a Digital Volt meter over a test light. Does everything else work, turn, park and brake lights? Are you doing the test the plugs connected together? Give me more info. Also some of the 5 pin flats have a option for either the brake control or 12v aux.