Tired of Your Truck’s Unpredictable Electronics?
If your GMC Sierra or another GM truck is plagued by flickering lights, a dead instrument cluster, unresponsive power windows, or a persistent airbag light, you’re likely dealing with a failing Body Control Module (BCM). As the central nervous system for your vehicle’s comfort and security features, a faulty BCM can turn your reliable workhorse into a source of daily frustration. In my 20+ years of diagnostics, I’ve seen these modules cause some of the most confusing symptoms, often leading owners and even other shops down a rabbit hole of expensive, unnecessary repairs.
This OEM-quality Body Control Module, equivalent to part number 20939138, is the definitive solution. We take the guesswork and high dealership costs out of the equation. Before we ship it, we program the module to your vehicle’s specific VIN. This ensures that when it arrives, it’s a true plug-and-play replacement, ready to restore full functionality right out of the box. Stop chasing electrical gremlins and get the reliable fix your truck deserves.
Case Study: A Tricky Diagnosis
A customer brought in his 2011 Sierra 2500 with a bizarre list of complaints: the radio would cut out on bumpy roads, the driver’s side window worked intermittently, and the airbag light (with a stored DTC B1001) was always on. He’d already replaced the window switch and checked fuses. After confirming power and ground at the affected components were unstable, my attention turned to the BCM. These modules are notorious for developing internal connection failures over time. We installed one of our VIN-programmed BCMs, and in less than 10 minutes, every single issue was resolved. The key was having a module correctly configured for his truck’s options, which prevented any communication errors with the other onboard systems.
Is Your GM Truck Showing These Telltale Signs?
- ✔ The air conditioning or heater blower motor works sporadically or not at all.
- ✔ Your airbag warning light is illuminated, often with a Diagnostic Trouble Code (DTC) like B1001.
- ✔ Power accessories like door locks, windows, or interior lights have a mind of their own.
- ✔ The security system acts up, causing no-start conditions, stalling, or random alarms.
- ✔ You’re seeing multiple communication error codes (U-codes) when you scan the vehicle.
- ✔ The horn honks unexpectedly or doesn’t work when you press it.
Your 5-Minute Path to a Fully Functional Truck
Replacing the BCM is one of the easier electronic repairs you can perform. It’s typically located under the driver’s side dashboard, near the steering column. No complex tools are needed.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- Locate the Module: Find the BCM under the dash. It will have several large multi-pin connectors attached to it.
- Disconnect and Remove: Carefully press the release tabs on each electrical connector and pull them straight out. Then, unclip or unbolt the old BCM from its mounting bracket.
- Install the New BCM: Snap the new, pre-programmed BCM into the mounting bracket. Firmly reconnect all electrical connectors, ensuring they click securely into place.
- Reconnect and Test: Reconnect the negative battery terminal. Start the vehicle and test all functions: lights, windows, locks, HVAC, and wipers to confirm the repair was successful.
Verified Fitment for Your GM Truck or SUV
This module is a direct replacement for a wide range of General Motors vehicles from 2007-2013, ensuring OEM-level performance. It is interchangeable with part numbers 25844480, 25971917, 15901388, 20939137, 22860591, and others. Please verify your part number or use our fitment tool to ensure compatibility with your specific model, including:
- Chevrolet Silverado & GMC Sierra 1500/2500/3500 (2007-2013)
- Chevrolet Tahoe & GMC Yukon / Yukon XL (2007-2011)
- Chevrolet Suburban 1500 / 2500 (2007-2011)
- Chevrolet Avalanche 1500 (2007-2011)
- Cadillac Escalade / ESV / EXT (2007-2011)
Frequently Asked Questions
What does a Body Control Module do?
The BCM acts as the main computer for your vehicle’s body electronics. It controls non-engine related functions like your lights, power windows, door locks, security system, climate controls, and wipers.
Why is VIN programming so important?
Programming the BCM with your vehicle’s VIN ensures it communicates correctly with all other modules (like the ECU and airbag system) and is configured for your specific options (e.g., power seats, sunroof). This service saves you a trip to the dealership and guarantees a plug-and-play installation.
Is this a difficult part to install myself?
Not at all. For most DIYers, this is a very straightforward job that takes less than 15 minutes. The module is easily accessible under the driver’s side dash, and no special tools are required for the physical replacement.
What if my airbag light is still on after installation?
In some cases, particularly if the old BCM failed and set a hard code, you may need to perform a ‘Setup SDM Primary Key in BCM’ procedure. This requires a professional-grade scan tool and re-syncs the new BCM with the airbag system to clear the light.
Do I need to send my old BCM back?
No. There is absolutely no core charge for this part. You can keep your old module without any extra fees or hassle.
How do I know this part number will fit my truck?
The best way is to match the part number from your original BCM. This module (20939138) interchanges with many others, including 25844480. You can also use the fitment chart on this page or contact us with your VIN for guaranteed compatibility.