Troubleshooting Dexter Electric Over Hydraulic Actuator Pump Working On Its Own

Updated 11/13/2017 | Published 11/11/2017

Question:

Hi I have a dexter K71-651 elect/hyd pump and it sometimes starts working on its own but not at full presure as if the B/A switch is activated. Just asif its working at a low preasure..... ? What could cause this ?

asked by: Marcel D

Expert Reply:

The Dexter DX Series Electric Over Hydraulic Brake Actuator for Disc Brakes - 1,600 psi # K71-651 should not be running on its own. It does have an automatic prime, but the brakes should not apply even slightly without your controller.

To troubleshoot, the first thing you will need to do is check that all of the wiring of the actuator and your brake controller are correct. I attached a couple diagrams that should be helpful

I spoke with my contact at Dexter and there is a way to troubleshoot your actuator. If you use a 12 volt battery and connect just the white wire from the actuator to the negative post and then connect the black wire to the positive side of the battery, you could possibly hear a click sound but the actuator should not turn on. If it does turn on and run, the unit is defective and needs to be replaced. This would be done without having the blue wire connected.

Wiring connections for the Electric Over Hydraulic Brake Actuator are as follows:
Yellow - Cold side of breakaway switch, The wire that goes hot when a breakaway occurs.
Black - Positive connection on breakaway switch, The wire that charges the breakaway battery.
Blue - Output from in cab controller, The wire that provides power from your brake controller.
White - Ground

expert reply by: Jason S