Troubleshooting the Hydrastar Electric Over Hydraulic Actuator w/ a GMC Factory Brake Controller
Updated 12/22/2025 | Published 10/22/2024
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Question:
I have a 2020 GMC 3500HD with integrated brake controller. I am towing a 2023 Riverstone Legacy 5th Wheel with Hydrastar HBA-16 disk brake actuator. Everything works fine most of the time, however while towing I will suddenly, intermittently get a message on the dash that says service trailer wiring, resulting in loss of brakes. Trailer lights continue to work fine. Over time, the error clears and I have trailer brakes again. I have not been able to figure out what conditions bring this error on. It can be a cloudy day or sunny day. The video and description of this adapter states for GM vehicles to present, but I see the reference that 2018 does not need it. Do you think this adapter would resolve my issue or has GM resolved the issue since and my problem is something different? I also have 600w of solar and 4 100ah lithium batteries. I did read something that maybe the truck brake controller is checking the trailer battery voltage causing the error. Any help would be much appreciated. Thank you
asked by: David M
Helpful Expert Reply:
Hey David! It sounds like your factory controller isn't communicating reliably with the Hydrastar Electric Over Hydraulic Actuator for Disc Brakes item # HBA16. Even though the item # HBA16 says it's compatible with your 2020 GMC's factory brake controller It is advised if you're having the issues you're describing to use the Hydrastar Electric Over Hydraulic Actuator Adapter Module item # HBA-CAM.
Product Page this Question was Asked From
Hydrastar Electric Over Hydraulic Actuator Adapter Module for Ford and Chevy Brake Controllers
- Accessories and Parts
- Brake Actuator
- Disc Brakes
- Hydraulic Drum Brakes
- Adapters
- Hydrastar
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Jerred H.
12/22/2025
Hey David, how did things go after adding the Hydrastar adapter module to your GMC’s brake controller setup? Did it clear up the intermittent “service trailer wiring” error you were seeing? Your update could make it easier for others towing with similar Hydrastar systems.