I was trying out the trailer brakes today (first time i've used these) and while i'm driving, if I press in the clutch and brake at the same time, the trailer wheels lock up. Its a Redline brake controller in a 92 chevy 2500, 5sp manual. if the clutch is not pressed in, the brakes work fine. As soon as I press in the clutch, they lock up. Doesn't matter if i'm in LL, 1, 2, 3, OD, or no gear at all. I'm assuming its a wiring problem. The controller came with the truck when I bought it. Any ideas?