Troubleshooting Jerking Motion From Brake Controller When Not Applying Brakes  

Question:

Expert Reply:

It sounds like you have a short somewhere that is kicking on and off due to vehicle or trailer position as you drive. The likely culprits are the trailer connectors on the vehicle and trailer. You will need to make sure that the connectors are clean and free of corrosion inside and out.

To test the controller use a circuit tester such as # PTW2993. Probe the blue wire a few inches from the back of the controller and test the end coming out of the controller while fully applying the manual override. The controller should only show increasing power when the manual override is pressed. Power at any other times indicates a problem inside the controller and it will need to be replaced.

You will also want to check the red wire connection on the controller. It should only have power when you step on the brake pedal. If it shows power at any other time then you are likely connected to the wrong wire.

If the brake controller checks out fine then check the brake output blue wire from the controller to the connector looking for any loose or frayed wires and fix as needed.

On the trailer side you will want to inspect the brake magnet wiring the same way. Make sure the grounds are connected to clean and corrosion free bare metal surfaces. Then visually inspect the magnets and if you can see the windings coming through they will need to be replaced.

To further test the magnets you can follow the how-to article I have linked. I have also linked a couple on brake controllers for you.

expert reply by: Jason S

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