I bought a used trailer and put all new lights wires and breaks on it. I hooked up the breaks last weekend and they were all humming nice and loud. I took it for a test ride and turned the gain all the way up because I wasn't feeling much braking. Right rear wheel locked up on gravel but the others kept spinning. I thought maybe grease got through the seals and buttered up the brakes on the others but this weekend I took apart the front left and it all looked good. I put it all back together and now I don't get any hum on anything except for when the override is squeezed. Looking at the dash it says trailer brakes connected. I can change the gain but the indicators don't light up when I step on the brake. I checked the fuse and it's good. I jammed a snow brush between the seat and peddle and tested the junction box and I only have a reading of 0.5 on average it fluctuates. It never hits one volt. Anyone have any ideas?