I have a X3 and a car trailer. I hooked them up and they seemed to work ok, not great as the brakes seemed to want to grab the wheel at slow speed. Ok at highway speed braking. It got worst on the way home. Now the right wheel rear want to go on full brake when you touch the brake.

I just got back and the brake want to come on full when you just touch the brake. Do I need to get a brake controller wired in?

I have the same problem - Did you get it resolved, and if so, how?