Restore Safe Towing and Eliminate Annoying Dash Warnings
If you’re staring at the dreaded “Service Trailer Brake System” message on your 2013-2014 GM HD truck, you’re not alone. As a technician with over two decades of experience, I’ve seen this issue countless times. It’s more than an annoyance; it’s a critical safety failure that leaves you without proper control over your trailer’s brakes. This Trailer Brake Control Module (TBCM), part number 20964299, is the definitive, reliable solution to get you back on the road with confidence and peace of mind.
What makes this part the best choice for your repair? We take the hassle and expense out of the equation. Unlike a standard replacement part that requires a trip to the dealership for costly programming, this module arrives at your door completely pre-programmed to your truck’s specific Vehicle Identification Number (VIN). Using the latest GM software, we ensure it’s a true plug-and-play component. You simply provide your VIN at checkout, and we handle the rest, saving you time, money, and a trip to the service bay.
Case Study: A Tricky Diagnosis
I once had a 2013 Silverado 2500 in my shop with an intermittent “Service Trailer Brake” light. The customer explained it only happened after driving on wet roads. We checked the wiring and connectors, which seemed fine. After hooking up my scan tool, I found communication loss codes for the TBCM. Because these modules are mounted on the frame rail, they’re constantly exposed to water, salt, and debris. Over time, moisture seeps past the seals, causing internal corrosion and failure. We replaced the old unit with a pre-programmed TBCM, and the problem was solved instantly. This is why a high-quality, properly sealed replacement is non-negotiable for a lasting repair.
Is Your Truck Displaying These Warning Signs?
A failing TBCM doesn’t always present the same way. If you’re experiencing any of the following, this module is the likely solution.
- ✔ Persistent “Service Trailer Brake System” message on the driver information center (DIC).
- ✔ “Trailer Connected” or “Trailer Disconnected” messages cycling randomly, even with no trailer attached.
- ✔ No output or weak output from the manual trailer brake controller slide.
- ✔ Complete inability for the truck to detect a connected trailer.
- ✔ Diagnostic Trouble Codes (DTCs) stored in the system, such as C0299, C1512, C1521, or U0100 series codes indicating a loss of communication.
A Straightforward Guide to Installation
Thanks to our VIN programming service, installing your new 2013-2014 Sierra 2500 Trailer Brake Module is a job most DIYers can handle in their own driveway. Follow these steps for a successful replacement.
- Safety First: Disconnect the negative terminal from your truck’s battery to prevent any electrical shorts.
- Locate the Module: On most pickups, the TBCM is mounted to the driver’s side frame rail, typically near the rear axle. On Suburbans and Yukons, it’s often on the driver’s side frame rail, closer to the middle of the vehicle.
- Disconnect Wiring: Carefully unplug the electrical connectors from the old module. Press the release tabs firmly and pull straight out. Inspect the connectors for any corrosion or damage.
- Remove the Old Module: Unbolt the old TBCM from the frame. These bolts may be rusty, so applying a penetrating oil beforehand can be helpful.
- Install the New Module: Bolt your new, pre-programmed TBCM into place. Ensure it is securely fastened to the frame.
- Reconnect and Test: Plug the electrical connectors firmly into the new module. Reconnect your battery terminal. Start the truck and verify that the “Service Trailer Brake System” message is gone. If you have a trailer, connect it to test full functionality.
Verified Vehicle Compatibility
This module is a guaranteed direct-fit replacement for the following vehicles equipped with the factory towing package. It is a compatible replacement for part numbers 20964299 and 20850923.
- ✔ 2013-2014 GMC Sierra 2500 / 3500 (including Denali)
- ✔ 2013-2014 Chevrolet Silverado 2500 / 3500
- ✔ 2013 Chevrolet Suburban 2500
- ✔ 2013 GMC Yukon XL 2500
Frequently Asked Questions
Why do you need my VIN?
Your vehicle’s VIN is required so we can program the module with the correct software and calibrations for your specific truck. This ensures it communicates perfectly with your vehicle’s other systems, making the installation truly plug-and-play without needing a trip to the dealer.
Where do I provide my VIN?
After you complete your purchase, you will need to send us a message with your 17-digit VIN. We cannot ship the part until we receive this information to complete the programming.
Is this part difficult to install?
Not at all. Since the module comes pre-programmed, it’s a simple unbolt-and-replace procedure. It typically involves removing a few bolts and unplugging electrical connectors. Most people with basic hand tools can complete the job in under an hour.
Will this fix the ‘Service Trailer Brake System’ warning?
In the vast majority of cases, yes. A faulty TBCM is the most common cause of this warning message on these GM trucks. This part is designed to be the definitive solution for that specific problem.
What is the difference between this and a part from the auto parts store?
A standard part from a local store or online retailer will not be programmed. You would have to install it and then take your truck to a dealership or equipped repair shop to have them program it, adding significant cost and inconvenience to the repair. Our service eliminates that step entirely.