P3 and P2 Brake Controllers Show Overload Error on 2003 Ford Super Duty

Question:

2003 Ford super duty P 3 controller Montana 5th wheel. Loss of brakes whether using of not. In process of replacing wheel trailer mags. Also did this with P 2 controller. Have replaced both sides of towing connection. Controller says overload. It reconnects then disconnects at will. Sometimes it takes many miles before this occures. Acts like something gets hot. Running out of ideas.

asked by: Cliff

Expert Reply:

It could be a short on the blue wire which is the brake output wire. When you replace the magnets make sure that they are grounded to a clean and corrosion free bare metal surface near the magnets. Also make sure none of the wiring to the magnets is pinched or frayed and fix as needed.

Check the trailer and vehicle side connectors to make sure they are free of corrosion inside and out (including where the wires attach at the back). I have included some links on testing and troubleshooting brake controllers for you.

You can also check the position of the wires on the end of the brake controller harness that plugs into the truck. It should look like the picture I have included. If the wires are in different locations on the connector you are using then move the wires as needed.

If you hardwired in the controller then it is possible that the red wire is connected to the wrong brake switch wire. It needs to go to the one that only has power when the brake pedal is pressed and not when the head lights or turn signals are on.

Also, if hardwired in, make sure the controller is grounded to the negative battery terminal. No other ground location will do.

expert reply by: Michael H