Restore Full Electrical Function to Your GM Truck
Are you dealing with baffling electrical issues in your truck? Flickering lights, unresponsive power windows, or a climate control system with a mind of its own? These are classic signs of a failing Body Control Module (BCM), the electronic nerve center of your vehicle’s comfort and security features. This replacement BCM, part number 20939137, is the definitive solution for your 2007-2011 Sierra 1500 and a wide range of other GM trucks and SUVs. We take the guesswork and dealership hassle out of the repair by pre-programming the module to your vehicle’s specific VIN. This ensures it works correctly right out of the box, restoring functionality and peace of mind.
Case Study: A Tricky Diagnosis
I remember a 2009 Silverado that came into the shop with a laundry list of complaints: the radio would cut out, the driver’s side power lock was dead, and the A/C blower was intermittent. The owner had already replaced the battery and checked fuses. After hooking up the scanner, I saw a dozen communication codes. The root cause wasn’t any single component but a corroded BCM ground connection under the dash. This poor ground had slowly damaged the internal circuits of the original BCM. We replaced it with a pre-programmed module like this one and cleaned the grounding point, which permanently solved all the issues. It’s a perfect example of why a quality part and a thorough check of the basics are key to a lasting repair.
Is Your Sierra Showing These Electrical Faults?
A failing BCM can cause a cascade of problems that seem unrelated. If you’re experiencing any of the following, your BCM is the most likely culprit. This module is engineered to resolve these common issues.
- ✔ Power accessories (windows, door locks, mirrors) working intermittently or not at all.
- ✔ HVAC system failures, such as a blower motor that won’t turn on or stays stuck on high.
- ✔ The security system light flashing, causing a no-start or stalling condition.
- ✔ An airbag warning light on the dash, often with a diagnostic trouble code (DTC) like B1001.
- ✔ Headlights, taillights, or interior lights behaving erratically.
- ✔ Communication errors with other vehicle modules, leading to various warning lights.
A Straightforward Guide to Installation
One of the best features of this module is the simple, DIY-friendly installation process. You can have your truck back to normal in under 15 minutes without needing a trip to the dealership.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before working on any electronics.
- Locate the BCM: On most GM trucks and SUVs of this era, the BCM is located under the driver’s side of the dashboard, near the steering column.
- Remove the Old Module: Carefully unplug the electrical connectors. They have locking tabs that need to be depressed. Once unplugged, the module can be unclipped or unbolted from its bracket.
- Install the New Module: Seat the new, pre-programmed BCM into the mounting bracket and securely plug in all the electrical connectors. You’ll hear a click as they lock into place.
- Reconnect and Test: Reconnect the negative battery terminal. Start the vehicle and test all functions—windows, locks, lights, wipers, and HVAC—to confirm the repair was successful.
Post-Installation Procedures for a Perfect Fix
While our VIN programming handles the vast majority of setup, some vehicle systems may require a quick sync after installation. If the airbag light remains on, a professional scan tool is needed to perform the ‘Setup SDM Primary Key in BCM’ function. In some cases, a ‘Brake Pedal Position Relearn’ may also be necessary. And remember, there’s no core charge, so you can keep your old part without any extra hassle.
Verified Vehicle Compatibility
This BCM is a direct replacement for part number 20939137 and interchanges with several other part numbers, including 25844480, 25835966, 15943678, and more. It offers guaranteed fitment for a wide array of General Motors vehicles, including:
- Chevrolet Avalanche, Silverado 1500/2500/3500, Suburban, Tahoe (2007-2013)
- GMC Sierra 1500/2500/3500, Sierra Denali, Yukon, Yukon XL (2007-2013)
- Cadillac Escalade, ESV, EXT (2007-2011)
Please use the fitment checker to confirm this is the correct part for your specific year and model before ordering.
Frequently Asked Questions
What exactly does a Body Control Module do?
The BCM acts as the central computer for your vehicle’s body electronics. It controls non-engine related functions like your lights, power windows and locks, security system, wipers, and climate control, ensuring everything works together seamlessly.
Is this part really plug-and-play?
Yes. We program the module with your vehicle’s VIN before shipping. This ensures it communicates correctly with your truck’s other systems, eliminating the need for expensive dealership programming. For most installations, it’s a direct swap.
What if my airbag light is still on after I install this BCM?
This can happen. It means the new BCM needs to be electronically ‘introduced’ to the airbag system’s computer (SDM). A mechanic with a professional-grade scan tool can perform the ‘Setup SDM Primary Key in BCM’ procedure in a few minutes to clear the light.
Why is checking the ground connection so important?
As my shop story illustrates, a bad ground is a common cause of BCM failure. A poor connection can cause voltage spikes or drops that damage sensitive electronics. Ensuring the ground is clean and tight during installation prevents the new module from failing prematurely.
Do I have to send my old part back?
No. This product comes with no core charge. You can keep your original module without any extra fees or hassle, simplifying the repair process for you.
How can I be sure this fits my 2007-2011 Sierra 1500 BCM?
This module is a direct fit for the 2007-2011 GMC Sierra 1500. It also replaces numerous other part numbers. To be 100% certain, you can match the part number from your original module to the list of interchangeable parts on this page or use our vehicle fitment tool.