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2024 - 2025 GM Controller Adapter Module [381-7074] [*381-7075] - Hydrastar

2024 - 2026 GM Controller Adapter Module [381-7074] for Electric Over Hydraulic System

SKU *381-7074
by Hydrastar
Save 19% Save 19%
$85.00
$85.00 - $85.00
$85.00
$69.00
$69.00 - $69.00
$69.00

Fixes the 2024–2026 GM Silverado, Sierra, and Denali “Service Trailer Brakes” dashboard warning. This plug-and-play inline diode resolves the compatibility issue between GM’s factory integrated brake controller and electric-over-hydraulic (EOH) trailers. Install takes minutes — cut the blue wire, crimp the module inline, done.

2024–26 GM Trucks
PLUG & Play
2 WIRE Install
American Flag Made in the USA
Questions about fitment?

Feel free to reach out to us or start a live chat in the bottom right corner for assistance.

The Problem

Why Your GM Truck Disables Trailer Brakes

GM’s 2024–2026 factory integrated brake controller sends a diagnostic signal down the blue (brake) wire. When it doesn’t get the response it expects from electric-over-hydraulic (EOH) systems, it triggers a fault — displaying “Service Trailer Brakes” on your dash and disabling braking. This module intercepts that signal and allows normal operation.

Specifications

Technical Details

Compatible Vehicles 2024–2026 GM Silverado, Sierra, Denali, and other models with factory integrated brake controllers
Brake System Electric-Over-Hydraulic (Eoh)
Installation Inline on the blue (brake controller) wire, ~10" from the actuator
Type 2-wire inline diode module
Effect on Other Vehicles None — does not affect non-GM tow vehicles
Part Number 381-7074
Common Questions

Before You Buy

Does this work with non-Hydrastar actuators?+
Yes. The 381-7074 works with any brand of electric-over-hydraulic (EOH) system.
How do I install it?+
Cut the blue wire approximately 10" from the actuator. Crimp the module inline — wires are labeled for direction. Heat shrink the connections. Arrow on the diode points toward the actuator.
Will this void my GM warranty?+
No. This module is installed on the trailer side, not the vehicle side.
My dealer told me about this — is this the right part?+
Yes. GM dealerships are actively referring customers to Hydrastar for this fix. Part #381-7074 for electric-over-hydraulic (EOH) trailers.

Reference: Vehicle Compatibility Chart (PDF)

Ford Owners

If you have a newer Ford and are experiencing connectivity issues before and after the flash — or when switching from electric mode to EOH mode — our part #381-7073 has been very successful in resolving trailer brake issues.

*This is not a Hydrastar issue. Ford has issued a recall affecting over 4.3 million vehicles due to a software issue. Our diode module helps Ford owners resolve their trailer brake connectivity problems.

Need Help Choosing?
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