Restore Critical Towing Safety and Clear Annoying Dash Warnings
If you’re seeing the dreaded “Service Trailer Brake System” message on your dash, you’re not just dealing with an annoyance—you’re facing a significant safety issue. As a technician with over two decades of experience, I can tell you that a faulty Trailer Brake Control Module (TBCM) means your trailer’s brakes aren’t getting the signal they need to activate. This can dramatically increase your stopping distance, especially with a heavy load. This genuine GM module, part number 20964299, is the definitive solution for your 2013-2014 GM HD truck, arriving at your door fully programmed and ready for installation.
The biggest headache with replacing electronic modules is the mandatory trip to the dealership for programming, which adds time and significant cost to the repair. We eliminate that step entirely. Simply provide your vehicle’s VIN during checkout, and our experts will flash this module with the latest, most stable software from General Motors. This ensures it communicates perfectly with your truck’s other systems right out of the box. This is the same process a dealer would perform, but done for you before it even ships. When it arrives, you can install it yourself and get back to towing safely and confidently.
Is Your Truck Showing These Symptoms?
- âś” “Service Trailer Brake System” message is constantly on or appears intermittently.
- âś” No output or weak output to the trailer brakes when manually applied or during braking.
- âś” The trailer gain display on your dash is blank or shows dashes.
- âś” Diagnostic Trouble Codes (DTCs) such as U0100 (Lost Communication With ECM/PCM), U0415 (Invalid Data Received From ABS Control Module), or various C-series codes related to trailer brake circuits.
- âś” The truck fails to recognize that a trailer is connected.
A Technician’s Notebook: The Telltale Signs of TBCM Failure
Just last month, a 2014 Silverado 2500 came into the bay. The owner, a contractor, was frustrated because his trailer brakes worked one day and not the next. The dash warning was intermittent. A quick scan showed a communication fault with the TBCM. Knowing the module’s location on these trucks (mounted to the frame rail), my first suspect was water intrusion. Sure enough, after lowering the spare tire for access, I found the module’s casing was compromised, and the connector pins showed early signs of corrosion. This is the most common failure I’ve seen in my shop for this exact part. The frame-mounted location exposes it to road salt, water, and debris, which eventually works its way past the seals. Replacing it with a pre-programmed unit like this one is the only reliable, long-term fix.
A Straightforward Guide to Installation
- âś” Safety First: Disconnect the negative terminal from your truck’s battery to prevent any electrical shorts.
- âś” Locate the Module: On most Sierra and Silverado pickups, the TBCM is mounted on the driver’s side frame rail, just ahead of the rear axle. You may need to lower the spare tire for easier access. For Suburban and Yukon XL models, it’s typically on the driver’s side frame rail, around the middle of the vehicle.
- âś” Disconnect and Remove: Carefully unplug the electrical connector. Press the release tab firmly. Then, remove the bolts or nuts holding the module to its bracket on the frame.
- âś” Install the New Module: Mount your new, pre-programmed TBCM onto the bracket and secure it with the original hardware. Reconnect the electrical harness, ensuring it clicks securely into place.
- âś” Final Steps: Reconnect the negative battery terminal. Start the truck and verify that the “Service Trailer Brake System” message is gone. It’s always a good idea to connect a trailer (if available) to confirm full functionality.
Guaranteed Fitment for Your GM HD Truck or SUV
This module is a direct-fit replacement for the original part on a range of vehicles. It is compatible with part numbers 20964299 and 20850923. Please verify your vehicle is on the list below for guaranteed compatibility:
- âś” 2013-2014 GMC Sierra 2500 / 3500 / Denali 2500 / Denali 3500 (Towing Control; LH rear frame)
- âś” 2013-2014 Chevrolet Silverado 2500 / 3500 (Towing Control; LH rear frame)
- âś” 2013 Chevrolet Suburban 2500 (Towing Control; LH middle of frame)
- âś” 2013 GMC Yukon XL 2500 (Towing Control; LH middle of frame)
Frequently Asked Questions
What does “VIN Programmed” mean?
It means we load the module with the specific software and calibrations for your exact vehicle using your VIN. This makes it a true plug-and-play part, saving you a costly programming fee at a dealership.
Do I need any special tools to install this 2013-2014 Sierra 2500 TBCM?
No special tools are required. Basic hand tools, such as a socket set to remove the mounting bolts and disconnect the battery, are all you should need for a successful installation.
Is this part compatible with part number 20850923?
Yes, this module, part number 20964299, is a fully compatible and updated replacement for the older part number 20850923.
Why should I buy this instead of a used one from a salvage yard?
A used module will not be programmed for your truck’s VIN and will likely cause communication errors. Furthermore, given that corrosion is the primary cause of failure, a used part carries a high risk of failing soon after installation. Our module is verified, cleaned, and programmed with the latest GM software for reliability.
How do I provide my VIN?
After you complete your purchase, you will need to send us a message with your vehicle’s 17-digit VIN. We cannot ship the module until we have this information to complete the programming.