Weak Trailer Brakes Using a Tekonsha P3 Trailer Brake Controller and 2010 Toyota Tundra  

Question:

Expert Reply:

First, since you have changed something on the braking system, it is recommended to go through and re-set the brake controller as if it were the first time. In doing so make sure that it is mounted within its range as described in the instructions and not tilted or turned to one side or the other.

With the controller mounted correctly and reset you can test the output from the controller. You do not necessarily want to go by what the display says so I recommend using a circuit tester like # PTW2993 if needed to test it.

Sever the blue wire behind the brake controller a few inches. Use the circuit tester to test the end from the controller while fully applying the manual override. If the test light gets bright you know it's putting out the right voltage. If not, yet the display says it is putting out 12 volts then you know there is something wrong with the controller.

After testing the controller, you can test the vehicle connector at the back of the truck. Use the circuit tester to test the pin in the 7:00 position while someone fully applies the manual override. If the light is dim at the connector but bright in the cab you know there is a loose connection or bad ground somewhere between the controller and the connector.

Also check the vehicle and trailer side connectors for dirt and corrosion. Corrosion can also build up in the back of the connectors where the wires attach. If everything checks out on the vehicle side that means the problem is on the trailer side.

Make sure all connections to the brakes are intact and that the grounds are connected to clean and corrosion free bare metal surfaces. Since the breakaway system can lock the brakes I do not think it is a brake magnet or adjustment issue.

expert reply by: Michael H

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