Just purchased 2002 viking 2480st pop up. This is our 1st camper and have been double checking everything before we take off on our 1st trip. The camper has electric drum brakes so I purchased a Teconsha P2 controller with plug in wiring harness to install on my 2004 silverado 1500. Upon testing the brakes last night ( hooked camper up and eased forward with gain up to 13 and pulling manual switch on the controller ) the brakes on the camper did not seem to work. I could hear what sounded like the magnets clicking hitting the drums but no resistance. Where should I start? Controller, shoes, wiring?