Regain Complete Control and Confidence When Towing
Is the dreaded “Service Trailer Brake System” message constantly lit up on your dash? Are you experiencing intermittent or non-existent trailer brake activation? A faulty Trailer Brake Control Module (TBCM) not only creates an annoying warning but poses a serious safety risk for you, your cargo, and everyone else on the road. This direct-fit replacement 20850923 trailer brake control module is the definitive solution to restore the integrated braking performance and peace of mind you expect from your GM truck.
Common Symptoms & Your Direct-Fit Solution
If you’re dealing with any of the following issues, a failing TBCM is the most likely culprit. This module is engineered to resolve these problems permanently:
- Persistent “Service Trailer Brake System” warning light
- “Trailer Connected / Disconnected” messages cycling on and off
- No power output to the trailer brakes
- Inability to adjust brake gain using the in-cab controller
- Diagnostic Trouble Codes (DTCs) related to the trailer brake control circuit
Unlike a generic part from a local store, we take the critical extra step of programming this module specifically to your truck’s Vehicle Identification Number (VIN) before it ships. This ensures seamless communication with your truck’s other computer systems, eliminating compatibility errors and the need for an expensive trip to the dealership for programming.
Features & Tangible Benefits
- ✔ Pre-Programmed to Your VIN: Arrives ready for installation right out of the box. No dealer flashing or special tools required, saving you time and hundreds of dollars.
- ✔ Flashed with Latest GM Software: We load the most current and stable software from General Motors, ensuring optimal performance and reliability.
- ✔ Restores Full Braking Function: Regain precise, proportional control of your trailer brakes for safer, smoother stops under any load.
- ✔ Direct OEM-Spec Replacement: Guarantees a perfect fit and flawless integration with your truck’s existing wiring and mounting points on the LH rear frame.
- ✔ Clears Dashboard Warnings: Permanently resolves the “Service Trailer Brake System” error, giving you a clean and error-free instrument cluster.
- ✔ Peace of Mind on the Road: 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 try to save a few bucks with a non-programmed module, only to find the dash warning never goes away. On these 2007-2009 GM trucks, the TBCM is not just a simple switch; it’s a smart module that must be digitally ‘introduced’ to the Body Control Module (BCM) and other vehicle systems. Our VIN-specific programming handles this handshake for you, making the installation a true plug-and-play process and ensuring the 20850923 trailer brake control module functions exactly as the factory intended.
Frequently Asked Questions
How do I provide my VIN for programming?
After you complete your purchase, simply send us a message with your 17-digit Vehicle Identification Number (VIN). We cannot ship your part until we receive this information, as the programming is a critical step in the process.
Will this fix the “Service Trailer Brake System” message?
Yes. In the vast majority of cases, a faulty module is the root cause of this specific warning message. Replacing it with this pre-programmed unit is the correct and reliable repair to clear the code and restore system functionality.
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 side), near the rear axle and spare tire. It’s exposed to the elements, which is often why the original units fail over time.
Is this a difficult part to install?
For someone with basic mechanical skills, this is a straightforward installation. It typically involves disconnecting the battery, unplugging two electrical connectors, and removing a few bolts. Since our module is pre-programmed, there is no complex computer work required on your end.
My old part has a different number on it. Will this still work?
Yes, this 20850923 trailer brake control module is the correct replacement for several earlier part numbers, including 25854535, 25788981, and 25907533. It is the updated component for the listed vehicle applications.