Will the Hayes Air Brake Control Work Towing a Trailer with Electric Over Hydraulic Brakes

Question

Question:

we have a freightliner pulling a 40 ft gooseneck the brakes on the trailer is disk with a electric motor that operates the hydraulic. will this unit operate it. if not could you please recomemd a unit that would

asked by: David B

0

Expert Reply:

Since your trailer has electric over hydraulic brakes the best way to go would be to use a electronic brake controller that is compatible with the electric over hydraulic brakes on your trailer. Even though your Freightliner has air brakes, there is still a brake circuit that activates the brake lights on the vehicle that can be used to activate an electric over hydraulic compatible brake controller.

The Hayes Air Utility Brake Control, item # HA100400C, can be used to power electric brakes but has not been tested with electric over hydraulic units, and is not recommended for this application. You would also need to contact the vehicle manufacturer or air brake system manufacturer to get the proper 3-way tees, tubing, and double check valves needed for the air brake system on your Freightliner.

I would recommend the P3 Brake Controller, item # 90195, which is compatible with the electric over hydraulic unit on your trailer and is very easy to setup and use.

You will need to hard wire the P3 in your Freightliner. First connect the white wire to a the negative battery terminal. Next connect the black wire to the Aux side of a 30 amp circuit breaker, item # PK54530. Then from the Bat side of the circuit breaker connect a wire to the positive post of the vehicle battery. An appropriate length of 10 gauge double bonded wire, item # 10-2-1, can be used to wire these connections.

Next, use a circuit tester, item # 3808 if needed, to find the stop light circuit at the brake pedal switch. Once the stop light circuit that activates only when the brake pedal is pressed is located connect the red wire from the brake controller to this wire.

Finally, run an appropriate length of 10 gauge blue wire, item # 10-1-1, from the blue wire on the brake controller to the electric brake control connection in the trailer connector at the rear of the vehicle.

I have included installation instructions for the P3 controller and for installing an electronic brake controller from scratch that should be helpful.