Troubleshooting Hydrastar HBA 16 Electric over Hydraulic Trailer Brake Actuator that Runs Constantly

Updated 04/30/2024 | Published 01/06/2020

Question:

Ive got a trailer with electric over hydraulic brakes ,trailer has deep cycle batteries for the rv furnace and lights .Occasionally the pump will run continuous , the only way to get it to stop is clip the wire ,if the batteries are low in the trailer will it cause this problem?

asked by: Bill R

Expert Reply:

It's possible. Here's Cargo Towing Solutions troubleshooting procedure for if the actuator won't run, or runs continuously:

Verify that the trailer and tow vehicle are wired according to the electrical schematic shown below.
Perform the following checks to determine if the unit is functioning properly:

With the unit running and brake pressure applied, determine that a minimum of 8.5 volts DC are reaching the Hydrastar's black wire. Check to see if the white ground wire runs directly to the tow vehicle ground. IT MUST NOT BE GROUNDED TO THE TRAILER ONLY. IT IS IMPORTANT THAT THIS GROUND WIRE RUNS DIRECTLY TO THE TOW VEHICLE'S BATTERY GROUND. NO EXCEPTIONS.

Detach all wires from the Actuator leaving only the blue, black, white and yellow or blue w/ white striped 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 needs repair.

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 needs repair.

Leave the white wire connected to the negative (-) terminal of the battery. Connect only the yellow or blue w/ white stripe wire to the positive (+) terminal of the battery. The motor should run and the unit should pressurize. If this does not occur, the unit needs repair.

If the unit checks OK, reconnect the wires leading to the trailer plug and repeat steps 2 through 4. If you do not get the same results as before, the problem is in the trailer wiring or the electronic brake controller.