Dexter Hydraulic Brake Actuator part # K71-650 Troubleshooting

Updated 06/30/2020 | Published 06/26/2020

Question:

My Dexter hydraulic brake actuator has quit working, and I am unsure where the problem lies. I am running a Tekonsha P3 controller. When I apply the brakes in the truck via the pedal or the manual slide on the controller, I get no activation from the hydraulic pump unit. I have verified that the 12V power source is providing power and the controller signal seems to be functioning - my test light is dim on the controller signal wire then brightens up as you slide the manual activation lever across. I disconnected the brake controller signal wire to the pump and when I touch it to the constant 12v power source, the pump comes on and builds pressure. As well, when I pull the break away switch, the pump doesnt run. Can you help?

asked by: Dustin S

Expert Reply:

Here is the troubleshooting guide for you to use to determine what in your system is failing you. Could be one of three components being wiring, brake controller or actuator and this will help you identify which one it is.

Detach all wires from the Dexter Axle E/H unit leaving only the blue, black, white and yellow wires. It is important that the unit is disconnected from any other wires going to the towing vehicle or breakaway switch and breakaway battery. Failure to do so may result in a faulty test.

Using a 12 volt battery, connect the white wire to the negative (-) terminal of the battery.

Connect the black wire to the positive (+) terminal of the battery. The motor should not run. If the motor runs, the unit may be defective.

Leave the white wire connected to the negative (-) terminal of the battery. Connect the blue and black wires together to the positive (+) terminal of the battery. The motor should run and the unit should pressurize. If this does not occur, the unit may be defective.

Leave the white wire connected to the negative (-) terminal of the battery. Connect only the yellow wire to the positive (+) terminal of the battery. The motor should run and the unit should pressurize.
If this does not occur, the unit may be defective.

If the unit checks OK, reconnect the wires leading to the trailer plug and repeat the steps at the trailer plug. If you do not get the same results as before, the problem is in the trailer wiring or the electronic brake controller.

expert reply by: Randy B