I recently installed a brake controller from scratch.. I followed step by step insturctions. I hooked my truck up to my trailer to test my brakes.. The decimal point on my Draw tite activator III is the only thing that shows up... I retraced all my wires and they all are hooked up correctly... I noticed that everytime I hit my brakes the in-line fuse is blown. Any suggestions. I hooked the red wire to my brake switch red only had power when brake was pressed.
Expert Reply:
It sounds as if the signal from the controller is not reaching the trailer. I would recommend you start by bench testing the brake controller. You have already verified that you are getting power to the controller, and that the red wire to the stoplight switch is going hot when the brake pedal is pressed. Next, use a circuit tester, like our part number 40376 on the blue brake output wire exiting the rear of the controller. Do you get power when the brake is pressed and the manual override switch is activated? If not, the controller is most likely defective. If you do get power, closely examine both the trailer connector socket on the vehicle and the plug on the trailer, making sure they are not damaged or corroded. If you can see corrosion on the pins or in the sockets, the corrosion might have spread to the interior of the plug or socket. This would prevent the brake signal from reaching the trailer. Use the circuit tester on the brake output pin on the socket on the vehicle while a helper applies the brakes and activated that override switch. If you get a signal on the tester here, then the problem is on the trailer. If you do not get a signal, the problem exists in the wiring between the trailer connector and the brake controller. you will have to trace the circuit looking for a broken or pinched wire. If everything on the vehicle side of the equation, then check the brake output wire on the trailer, again looking for pinched wires or worn inslulation that would allow the wire to short out and blow that fuse.
expert reply by: Mike L
