P2 Trailer Brake Controller Stopped Working with Brake Pedal on 2003 Toyota Tundra

Question:

I have the progidy P2 controller and the pigtail for a 03 Tundra. System was working fine but now is not. Display shows n.c. and then the two blue dots even though trailer is connected. I get no automatic trailer braking. But if I use the manual lever on the bottom the trailer brakes will work. I tried unplugging the unit as per instructions and waiting and also cleaning the contacts at the truck and the trailer but no change. Do I need a new controller? Thanks.

asked by: Rich F

Expert Reply:

You may have a bad connection on the red wire which is the input to the brake controller telling it that you are stepping on the brake pedal. Make sure that he pin in the connectors for the brake controller at the red wire location, both ends, is not corroded or damaged. You will also want to check the stop light or CHMSL fuses.

Also if you are using the plug in wiring harness # 3040-P you may need to check the alternate white ground wire and make sure it is attached to a clean bare metal surface. Moving it to a different, more substantial grounding location could help.

You will also need to make sure that the truck and trailer side connectors are clean and free of corrosion on the insides too, not just on the pins.

There are some tests you can do to determine if the controller is bad. First disconnect the trailer. In the truck cab you will need to sever the blue wire several inches from the back of the controller. Then use a circuit tester such as # PTW2993 if you need one to test the end of the blue wire coming out of the controller. It should only have power when you apply the manual override (or brake pedal for some controllers). If it shows power at idle, then there is something wrong with the controller and it will need to be replaced.

If the truck side checks out fine then it could be the wiring to the brake magnets or the magnets themselves. Inspect the power wires to the magnets and look for pinched, frayed, or damaged wires and fix as needed. Make sure the ground wires are attached to clean and corrosion free bare metal surfaces.

You can visually inspect the magnets and if you can see the copper windings coming through the magnets will need to be replaced. To further test the magnets you can follow the help article I have linked. I have also included some help articles on testing and troubleshooting brake controllers for you.