Troubleshooting Prodigy P3 Brake Controller On 2014 Toyota Tundra

Question:

I have a 2014 Toyota Tundra with the Tekonsha P3. It is set up for plug-and-play, so installing the brake controller was simple and no problems. I just installed new electric trailer brakes and new wiring including a new 7 pin trailer plug on a utility trailer. It has a single axle, 12inch drum brakes. After wiring, I jacked up the left wheel to test the brake, and everything worked properly when applying the manual brake on the P3. Then a few minutes later I switched to the right wheel and tested that brake. This time the P3 displayed no trailer connection, and no longer applies the brakes. The wiring and connections are good, the grounds are attached to clean frame metal, and nothing changed between the time I checked the left and right wheels. Is it possible there is a blown fuse somewhere or some other open circuit I can check for? Thanks in advance.

asked by: David

Expert Reply:

This is a tough one. Finding the source of the problem can be really tough and time consuming.

Unfortunately, if your P3 # 90195 is receiving power and showing a display, the problem will be in the wiring somewhere between the brake controller and the brakes, and not any of the fuses. When you said that the brakes are no longer being applied, I assume you are talking about both sides. If just the right side is not working, then the problem will be in the wire that splits on the harness and goes to both of the brakes.

You will need a circuit tester like part # PTW2993 to test the wires. First check the blue wire coming from the brake controller to make sure it is receiving current when applying the manual brake on the controller. If you have current, you will want to move to the Tundra wiring harness and test the current going in and coming out of the brake circuit. Then plug the trailer in and test the back of the trailer plug for current.

You will then need to keep checking the wiring back until you have verified current all the way to the brakes. If the problem is intermittent, you may want to make sure the wiring harness is grounded correctly and free of corrosion.

I have attached a couple of helpful articles and a drawing that you can check out.

expert reply by: Jeffrey L