Restore Towing Confidence and Safety in Your GM Truck
Seeing the ‘SERVICE TRAILER BRAKE SYSTEM’ message on your dash is more than an annoyance—it’s a critical safety alert. As a technician with over two decades of experience, I know that a failing Trailer Brake Control Module (TBCM) can leave you without proportional brake control when you need it most. This isn’t just about a warning light; it’s about the safety of your load, your truck, and everyone around you. This module is the direct-fit, reliable solution for your 2013-2014 GM HD truck, designed to restore full functionality and peace of mind.
The biggest hurdle with replacing modern electronic modules is the need for expensive, dealer-level programming. We eliminate that step completely. When you purchase this 2013-2014 Silverado TBCM, you provide us with your vehicle’s VIN. My team then flashes the module with the latest, most stable software from GM, specifically matched to your truck’s configuration. It arrives at your door ready to install, saving you a trip to the dealership and hundreds of dollars in programming fees. It’s a true plug-and-play fix.
From the Diagnostic Bay
I remember a customer with a ’14 Sierra 2500 who was chasing an intermittent trailer brake fault for weeks. His trailer brakes would sometimes work, sometimes not. He’d replaced the 7-pin connector and even re-wired part of his trailer, but the problem persisted. When he brought it to my shop, the codes were inconsistent. The first thing I checked was the TBCM on the driver-side frame rail. Just as I suspected, years of exposure to road salt and moisture had caused corrosion on the connector pins and compromised the module’s internal circuit board. A new, properly programmed TBCM fixed his issue instantly. These modules live in a harsh environment, and failure is a matter of when, not if.
Common Signs of a Failing TBCM
If you’re experiencing any of the following, a faulty TBCM is the most likely culprit. Replacing your 2013-2014 Silverado TBCM can resolve these issues:
- ✔ ‘Service Trailer Brake System’ warning on the Driver Information Center (DIC).
- ✔ No power output to the trailer’s electric brakes.
- ✔ The manual trailer brake controller slide does not activate the brakes.
- ✔ Diagnostic Trouble Codes (DTCs) stored in the system, such as C1512, C1520, or U0100 series communication codes.
- ✔ Intermittent connection or disconnection messages when a trailer is attached.
A Straightforward Guide to Installation
You don’t need to be a master mechanic to replace this module. With basic hand tools, you can get this job done in your own driveway.
- Safety First: Always disconnect the negative terminal from your truck’s battery before working on any electronic components.
- Locate the Module: On most pickups, the TBCM is mounted to the inside of the driver-side (LH) frame rail, roughly above the rear axle. On Suburbans and Yukons, it’s typically on the LH frame rail closer to the middle of the vehicle.
- Disconnect: Carefully unplug the electrical connectors from the module. Press the release tabs firmly and pull straight out. Inspect the connectors for any corrosion or damage.
- Remove the Old Module: The TBCM is usually held in place by two or three bolts. Remove these bolts and take the old module off the frame.
- Install the New Module: Mount your new, pre-programmed TBCM onto the frame and secure it with the original bolts.
- Reconnect and Finalize: Plug the electrical connectors securely into the new module. Reconnect your battery terminal. Start the truck and verify the ‘Service Trailer Brake System’ message is gone.
Guaranteed Fitment for Your GM HD Truck or SUV
This module is a direct replacement for part numbers 20964299 and 20850923, ensuring perfect compatibility with the following vehicles:
- ✔ 2013-2014 Chevrolet Silverado 2500 & 3500 Pickup
- ✔ 2013-2014 GMC Sierra 2500 & 3500 Pickup
- ✔ 2013-2014 GMC Sierra Denali 2500 & 3500
- ✔ 2013 Chevrolet Suburban 2500
- ✔ 2013 GMC Yukon XL 2500
Do I need to take my truck to the dealer after installing this?
Do I need to take my truck to the dealer after installing this?
No. We program the module to your truck’s specific VIN before we ship it. This means it is ready for installation right out of the box, with no additional programming or calibration required.
What do you need from me to program the module?
After you place your order, you will need to provide us with your 17-digit Vehicle Identification Number (VIN). We cannot ship the part until we receive your VIN, as the programming is essential for it to function correctly in your vehicle.
Is this part difficult to install for a DIYer?
Not at all. The module is typically mounted on the frame rail with just a few bolts. As long as you can safely access the area, the physical replacement is very straightforward. Our pre-programming service handles the difficult part for you.
Will this fix the ‘Service Trailer Brake System’ message?
In the vast majority of cases, yes. This warning message is the most common symptom of a failed TBCM. Provided the wiring and trailer-side components are in good condition, this module is the definitive fix.
What if I have a different part number?
This module, part number 20964299, is also a direct replacement for part number 20850923. If your original module has either of these numbers, this part is compatible.