I have a trailer that has on brake axle and the brakes aren't working that good. When I took the drum off the pads look good and aren't worn that much. When you press the brake you can hear them humming. When I depress the brake pedal while driving you can't hardly notice it pulling back. I also put a new brake away box on it, the one with the test light and battery built in, and when I pull the pin you can't hear anything and it doesn't lock down the brakes. I tested the blue wire going to the brakes with a test light and it is getting juice. Any ideas?