Restore Full Functionality to Your GM Truck with a VIN-Programmed BCM
If you’re dealing with baffling electrical issues in your 2007-2011 GMC Sierra 1500, you’re not alone. As a technician with two decades of diagnostic experience, I’ve seen firsthand how a failing Body Control Module (BCM) can turn a reliable truck into a source of daily frustration. This module is the central command for your vehicle’s body electronics. When it falters, you get unpredictable problems like intermittent A/C, malfunctioning power windows, or even a vehicle that refuses to start. This direct-replacement BCM, part number 20939138, is the definitive solution. We pre-program it to your truck’s specific VIN, so it arrives ready for a true plug-and-play installation, saving you a costly and time-consuming trip to the dealership.
A Technician’s Notebook: The BCM That Mimicked a Bad A/C Compressor
A customer brought in his 2009 Silverado with an A/C that only worked sporadically. He’d already replaced the blower motor resistor and was convinced the compressor was next. After hooking up my scanner, I saw no commands being sent from the HVAC controls. Instead of jumping to the expensive compressor, I checked the BCM data. The module was intermittently dropping communication. After a quick BCM swap with one of our programmed units, the A/C, power locks, and even a dim dome light he’d forgotten about all started working perfectly. It’s a classic case where the BCM, the vehicle’s electronic hub, was the true culprit, saving the customer hundreds in unnecessary repairs.
Is Your Sierra’s BCM Failing? Watch for These Signs
A faulty BCM can cause a wide range of confusing symptoms. If your truck is showing any of these signs, a failing 2007-2011 Sierra 1500 BCM is the most likely cause. Look out for these common indicators:
- ✔ The air conditioning or heater blower works intermittently or not at all.
- ✔ Your airbag warning light is on, often with a DTC like B1001 stored in the system.
- ✔ Power windows, door locks, or exterior lights behave erratically or fail completely.
- ✔ The anti-theft or security system malfunctions, causing no-start or stalling conditions.
- ✔ You’re pulling a variety of communication or body-related diagnostic trouble codes (DTCs).
- ✔ Unexplained battery drain when the vehicle is off.
A Straightforward Guide to Installation
One of the best features of this module is its simple installation. You don’t need to be a master mechanic to get this job done in your own driveway. Most installations take less than 10 minutes.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before working on electrical components.
- Locate the BCM: On most GM trucks of this era, the BCM is located under the driver’s side dashboard, to the left of the steering column. It’s a black box with several large multi-pin connectors.
- Swap the Modules: Carefully unplug the electrical connectors from the old BCM. It’s typically held in place by simple clips or a few small bolts. Remove the old module and install the new one in its place.
- Reconnect Everything: Securely plug all the connectors into your new BCM. Reconnect the negative battery terminal.
- Perform Relearns (If Needed): Start the vehicle. In most cases, you’re done! However, if your airbag light remains on, a professional scan tool is needed to perform the ‘Setup SDM Primary Key in BCM’ function. A Brake Pedal Position Relearn may also be required on some models to ensure proper brake light operation.
Verified Vehicle Compatibility
This Body Control Module is a direct replacement for part number 20939138 and is interchangeable with many other GM part numbers, including 25844480, 25835966, and 20939137. It offers guaranteed fitment for a wide range of General Motors trucks and SUVs. While this page is focused on the 2007-2011 Sierra 1500 BCM, it also fits the following vehicles:
- Chevrolet Avalanche: 2007-2011
- Chevrolet Silverado 1500/2500/3500: 2007-2011
- Chevrolet Suburban 1500/2500: 2007-2011
- Chevrolet Tahoe: 2007-2011
- GMC Sierra 1500/2500/3500 & Denali Models: 2007-2011
- GMC Yukon & Yukon XL/Denali: 2007-2011
- Cadillac Escalade, ESV, EXT: 2007-2011
Note: Some 2007 models are designated ‘new style’ (with a smooth door skin). This part fits those models. Always verify your part number for a perfect match.
Frequently Asked Questions
Frequently Asked Questions
What does ‘VIN Programmed’ mean for me?It means we load your vehicle’s unique Vehicle Identification Number (VIN) and all related factory software onto the module before we ship it. This ensures it communicates perfectly with your truck’s other computers right out of the box, eliminating the need for expensive dealership programming.