Troubleshooting EOH Brakes With Hydrastar Actuator Not Working With 2024 Ford F-450

Updated 03/27/2026 | Published 05/22/2025

Question:

I have a hydraster bracke actuator in my diamond c trailer, when I hook up my harness to my new truck, it doesn’t allow the brakes to activate but everything else on the trailer works. Can anyone here help me with this issue? Do I need to purchase an adapter to help it communicate with the truck?

asked by: Shane E

Expert Reply:

Hi Shane; sometimes the adapter module # HBA-CAM is needed to help the brakes function properly. However, before you go this route I would check out the brake controller. More often than not you need to switch to electric over hydraulic mode for the brakes to work with an actuator like the Hydrastar. If I had to guess, the brake controller is not set to EOH which is why it is not working properly.

expert reply by: Robin H

Adapter Module
(click to enlarge)

Shane E.

5/25/2025

I have checked the settings it is EOH. So that part is compatible with a 2024 f450?

Robin H.

5/25/2025

@ShaneE yes, it is compatible with any vehicle/setup.

Shane

6/4/2025

@RobinH hey so I bought that part that was suggested and my brake actuator still does not work with my 2024 f450, I’ve taken it to the dealer and they say there’s no issues with the truck so am I missing something? Does that part 100% work with this truck?

Robin H.

6/4/2025

@Shane it is not a truck dependent part. What it does is put enough load on the brake output circuit for the brake controller to think a trailer is connected. If you were to install this with something like the Prodigy P3 # 90195, which we know will work without it, it will not impact functionality of the brake controller and the Hydrastar actuator will still work as intended. It works with any brake controller on any vehicle. Do you get any errors when you're hooked up to the trailer? I think the best thing at this point is to run through everything with a circuit tester to try to narrow down the problem. I wouldn't uninstall the HBA-CAM at this point either since it can only help assuming it is properly installed. Since everything on the vehicle is theoretically working test the brake output on the trailer side while using the manual override to make sure power is getting through to the actuator and go from there. I doubt it is the trailer connector since you said everything else functions but it is still possible. Can you tell if the brakes are engaging at all while using the manual override? Is the Hydrastar actuator making a humming or buzzing sound indicating it is working?