How to Troubleshoot the Voltage From a Brake Controller on a 2005 Ford F-250 and F-350 Super Duty

Question:

I tested the voltage on the truck sitting still Im getting 2.3 volts at the plug. What should it be with the controller set to max? I think I might have a problem.

asked by: Tim J

Expert Reply:

If you have the controller set to max gain, then you should be getting 12 volts.

Instead of a voltage tester I strongly recommend using a circuit tester like part # PTW2993. The bulb will basically trick your brake controller into thinking that there is a trailer connected to it by placing a load on the circuit where a voltage meter does not. Some brake controllers will not send back full voltage if they don't sense a trailer is connected.

If you are using a proportional brake controller like the Tekonsha Prodigy P3 # 90195, the only way to see what the voltage is when using a tester is with the manual override lever. If you test the connection using the brake pedal while the vehicle is still, then the brake controller will recognize that the pressure put on the brakes is not really being used to stop anything and it will send a weak signal. If you use the manual override on your proportional brake controller while the circuit tester # PTW2993 is connected you will be able to test for voltage.

If you have a time delayed brake controller like the Tekonsha PowerTrac # 39523, then you will not have this problem.

If you are still not getting a reading under 12 volts when you check it through the trailer connector, there is still one more thing to check. Locate the blue wire that runs out from your brake controller, cut it about 6 inches away from the brake controller and then test the wire with the circuit tester. If you get 12 volts then your brake output wire between the brake controller and trailer connector is bad. You can either inspect the wire for any damaged sections or bypass the wire by running a new 10 Gauge Wire # 10-1-1 from the brake controller to the trailer connector. If you don't get a 12 volt reading then you will need to replace your brake controller.

I have attached some links and a help article for you as well.