Restore Safe and Reliable Towing to Your GM Truck
When you see the dreaded “Service Trailer Brake System” message on your dash, your truck’s most important capability is compromised. A faulty trailer brake control module (TBCM) isn’t just an annoyance; it’s a critical safety failure that puts you, your cargo, and others at risk. This replacement GM Trailer Brake Control Module 25854535 is the definitive solution to get you back on the road with the confidence and control you demand from your Sierra or Silverado.
Unlike a generic part from a local store, this module is not just a piece of hardware. It’s a complete, ready-to-install solution. We professionally flash the unit with the latest official GM software, programming it specifically to your truck’s Vehicle Identification Number (VIN). This crucial step ensures perfect communication between your truck and the module, eliminating the common compatibility errors that plague non-programmed units and saving you an expensive trip to the dealership.
Common Symptoms & Your Solution
If you’re experiencing any of the following issues, a failing TBCM is the most likely culprit:
- “Service Trailer Brake System” message appears on the Driver Information Center (DIC).
- “Trailer Connected” or “Trailer Disconnected” messages flicker intermittently.
- The trailer brakes do not engage or engage erratically when the pedal is pressed.
- Inability to adjust the trailer gain with the integrated controller switch.
- Diagnostic Trouble Codes (DTCs) such as C0561, U0100, or U0415 are stored in the system.
Installing this pre-programmed module is the most direct and reliable way to permanently resolve these problems and restore full, safe functionality to your integrated trailer braking system.
Features & Benefits
- ✔ VIN-Programmed for Your Truck: Arrives at your door flashed with the newest GM updates and calibrated to your specific vehicle. This eliminates the need for expensive dealer programming.
- ✔ Plug-and-Play Installation: Once programmed, this module is a direct-fit replacement. Simply locate the old unit on the driver-side rear frame rail, disconnect it, and install the new one.
- ✔ Restored Safety and Control: Regain precise, reliable control over your trailer’s brakes for safer stops and confident hauling in all conditions.
- ✔ Clear Dashboard Errors: Permanently resolves the “Service Trailer Brake System” warning, giving you a clean and error-free dash.
- ✔ Broad Compatibility: A direct replacement for part numbers 20850923, 25854535, 25788981, and 25907533.
- ✔ Guaranteed Performance: This unit is backed by our one-year replacement warranty.
An Expert’s Note on Programming
As a technician, I’ve seen countless truck owners waste time and money chasing trailer brake issues after installing a non-programmed module. These advanced systems are deeply integrated with your truck’s other computers, including the ECU and BCM. Without the correct VIN-specific software, the module simply can’t communicate properly, leading to the same errors you started with. Our programming service isn’t just a convenience—it’s the critical step that ensures the part works correctly the first time, just as the factory intended.
Don’t settle for a partial fix or risk your safety with a malfunctioning brake system. This professionally programmed GM Trailer Brake Control Module 25854535 is the correct, complete solution to get your truck back to work. Please provide your VIN at checkout to ensure we can program and ship your part without delay.
Frequently Asked Questions
Why is it essential to provide my VIN?
Your truck’s VIN allows us to load the exact, correct software and calibrations from GM for your specific model, year, and options. This step is mandatory and ensures the module will communicate flawlessly with your vehicle’s onboard computer systems, preventing errors and guaranteeing proper function.
Will this fix the “Service Trailer Brake System” message on my dash?
Yes. In the vast majority of cases, the persistent “Service Trailer Brake System” warning is caused by an internal failure of the original TBCM. Replacing it with this pre-programmed unit is the definitive repair for that issue.
Where is this module located on my truck?
The trailer brake control module is typically mounted to the frame on the driver’s side (LH), near the rear axle and spare tire. It’s a small black box with electrical connectors. Installation is generally straightforward for those with basic mechanical experience.
Is this part compatible with part number 20850923?
Yes, this module is a fully compatible and direct replacement for several part numbers, including 20850923, 25854535, 25788981, and 25907533. It will function identically once programmed to your VIN.
What happens if I forget to provide my VIN?
We cannot ship the module until we have your VIN to perform the necessary programming. If you forget to add it during checkout, our team will contact you, but this will delay the processing and shipment of your order.