Restore Safe Towing with a Plug-and-Play Trailer Brake Module
Seeing the ‘Service Trailer Brake System’ message on your dash is more than an annoyance—it’s a critical safety alert. When you’re hauling a heavy load with your 2013 Suburban 2500, Silverado, or Sierra, you depend on your trailer brakes to work flawlessly every time. A faulty Trailer Brake Control Module (TBCM) compromises that safety, leading to unpredictable or non-existent trailer braking. As a technician with over two decades of experience, I’ve seen firsthand how a failing TBCM can turn a routine tow into a hazardous situation. This isn’t a part you can afford to ignore.
We offer a straightforward, reliable solution. This genuine GM Trailer Brake Control Module (interchangeable with part number 20850923) arrives at your door fully programmed with the latest GM software, specifically matched to your vehicle’s VIN. This eliminates the most significant hurdle for DIYers and professional shops alike: the need for expensive and time-consuming programming at a dealership. You get a component that’s ready to install right out of the box, restoring full functionality and peace of mind.
From the Diagnostic Bay
I remember a customer with a 2014 Silverado 2500 who was chasing an intermittent ‘Trailer Connected / Trailer Disconnected’ message, even with no trailer attached. His trailer brakes would also apply erratically when he did tow. He had already replaced the 7-pin connector with no success. When I got the truck in my bay, I suspected the TBCM immediately. These modules are mounted on the frame rail, exposed to road salt, water, and debris. Upon inspection, I found the tell-tale signs of corrosion on the connector pins. Water had wicked its way inside, shorting out the delicate circuit board. Replacing the faulty module with a pre-programmed unit like this one solved all his issues in under 30 minutes. It’s a common failure point I’ve diagnosed hundreds of times on these GM HD platforms.
Common Signs of a Failing TBCM
If your truck or SUV is experiencing these issues, a faulty TBCM is the most likely culprit. Don’t let these symptoms put your safety at risk.
- ✔ ‘Service Trailer Brake System’ message on the Driver Information Center (DIC).
- ✔ No output or gain control to the trailer brakes.
- ✔ Trailer brakes are locked up or dragging.
- ✔ Intermittent ‘Trailer Connected’ message without a trailer hitched.
- ✔ Diagnostic Trouble Codes (DTCs) stored, such as C0561, U0100, or other communication faults related to the TBCM.
A Straightforward Guide to Installation
Installing your new 2013 Suburban 2500 TBCM is a job most DIYers can handle with basic tools. The key is knowing where to look. Always perform this work with the vehicle safely supported.
- Safety First: Disconnect the negative terminal from your vehicle’s battery.
- Locate the Module: On the Suburban 2500 and Yukon XL 2500, the TBCM is mounted to the inside of the driver’s side (LH) frame rail, roughly in the middle of the vehicle. On Silverado and Sierra pickups, it’s located on the driver’s side (LH) frame rail, further back towards the rear axle.
- Disconnect Electrical Connectors: Carefully press the release tabs and unplug the two electrical connectors from the old module. Inspect the harness connectors for any signs of corrosion or damage.
- Remove the Old Module: The module is typically held to the frame by two or three bolts. Use the appropriate socket to remove them and take the old module off the vehicle.
- Install the New Module: Mount your new, pre-programmed TBCM onto the frame and tighten the bolts securely.
- Reconnect and Finalize: Plug the electrical connectors firmly into the new module until they click. Reconnect the negative battery terminal. Start the vehicle and verify the ‘Service Trailer Brake System’ message is gone.
Verified Vehicle Compatibility
This module is a direct-fit, programmed solution for the following GM vehicles. Please provide your VIN at checkout to ensure perfect compatibility.
- ✔ 2013-2014 GMC Sierra 2500 / 3500 / Denali 2500 / Denali 3500
- ✔ 2013-2014 Chevrolet Silverado 2500 / 3500
- ✔ 2013 Chevrolet Suburban 2500
- ✔ 2013 GMC Yukon XL 2500
Frequently Asked Questions
Frequently Asked Questions
Why do you need my VIN?
Your vehicle’s Vehicle Identification Number (VIN) allows us to program the module with the exact software and calibrations specified by GM for your truck’s specific options. This ensures it communicates correctly with other systems, like the ECU and ABS module, making it a true plug-and-play part.
Do I need to take this part to a dealer after installation?
No. The main benefit of our service is that the module comes fully programmed. Once you install it, the repair is complete. You save the time, cost, and hassle of a dealership appointment for programming.
Is this a difficult part to install myself?
For most individuals with basic mechanical skills, this is a very manageable job. It involves unplugging connectors and removing a few bolts. The most challenging part is often just accessing the module on the frame rail. Please refer to our installation guide above.
Will this fix the ‘Service Trailer Brake System’ message?
In the vast majority of cases, yes. The TBCM is the most common point of failure that triggers this specific warning message on these GM trucks and SUVs. This part is designed to be the definitive solution for a faulty module.
What is the difference between part numbers 20964299 and 20850923?
These are interchangeable GM part numbers for the same component. GM often updates part numbers over time. Both part numbers are compatible and will function identically once programmed for your vehicle.