campbud
I also had brake problems, and it was a short in the brake drum. It shorted out on what I call the swing arm with the magnet on the end. There is suppose to be two clips to hold the wire from moving. To find which wheel is the problem, (others on the forum may have different ways). What I did, was jack up one wheel at a time and have some one apply the brakes and try to rotate the wheel back and forth to see if it shows up on the brake controller. If that doesn't work, I cut the wire to one of the wheels (one at a time) rather then taking all the wheels off to check it for a short. If it isn't that one, try the next one. When you find the one that doesn't show a short, that is the wheel, then pull the wheel off and drum. You have to look very close at the wire to find the short. When done I solder the wires then use a wire nut, then tape it, then a zip tie on the tape. Just my two cents worth, hope you find your problem.
Happy Camping
Larry & LaVonne