Restore Full Electrical Control to Your GM Truck
Are you dealing with baffling electrical issues in your truck? One minute the A/C works, the next it doesn’t. The power locks have a mind of their own, and a persistent airbag light is staring you down. These aren’t just annoyances; they’re classic signs of a failing Body Control Module (BCM). This module is the central command for your vehicle’s body electronics, and when it falters, it can cause a cascade of frustrating problems. This replacement BCM, equivalent to part number 20939137, is the definitive solution for your 2007-2011 Silverado 3500 BCM and a wide range of other GM trucks and SUVs.
From the Diagnostic Bay: The Case of the Haunted Silverado
I had a 2010 Silverado 2500 roll into my shop last month with a laundry list of complaints from the owner. The radio would cut out, the dome light would flicker, and the driver’s side window wouldn’t roll down. He’d already replaced the battery and checked the fuses. After connecting my scanner, I saw a handful of communication codes and a specific B1001 for the airbag system. Before condemning the BCM, I always check the main ground points, especially the one under the driver’s side A-pillar trim—they’re notorious for corrosion. In this case, the ground was solid. The culprit was, as suspected, an internally failing BCM. Installing a VIN-programmed module like this one resolved every single issue in under 10 minutes, saving the customer a tow to the dealership and a hefty programming bill.
Is Your Truck Showing These Symptoms?
A faulty BCM can manifest in numerous ways. If you’re experiencing any of the following, it’s highly likely your BCM is the root cause:
- ✔ Intermittent or non-functional HVAC and climate controls.
- ✔ Power windows, door locks, or mirrors operating erratically or not at all.
- ✔ An active airbag warning light on the dash, often with a DTC B1001 stored.
- ✔ Vehicle security system faults, including no-start or random stalling conditions.
- ✔ Exterior or interior lights that won’t turn on or off correctly.
- ✔ A variety of communication-related Diagnostic Trouble Codes (DTCs).
A Straightforward Guide to Your BCM Replacement
One of the best features of this module is its simple, DIY-friendly installation process. No need to schedule a costly appointment with a dealership. Just follow these steps:
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before working on any electronic components.
- Locate the BCM: On most GM trucks and SUVs of this era, the BCM is located under the driver’s side of the dashboard, often to the left of 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 BCM: Seat the new, pre-programmed module 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: lights, locks, windows, wipers, and HVAC to confirm the repair.
- Post-Installation Checks: If the airbag light remains on, an “SDM Key Update” may be needed using a bi-directional scan tool. This syncs the new BCM with the airbag system. Similarly, a Brake Pedal Position relearn might be required on some models.
Guaranteed Fitment for Your GM HD Truck
This Body Control Module is a direct replacement for part number 20939137 and other interchangeable numbers. It is guaranteed to fit the following vehicles:
Chevrolet:
AVALANCHE 1500: 2007-2011
SILVERADO 1500 PICKUP: 2007-2011
SILVERADO 2500 PICKUP: 2007-2011, 2013
SILVERADO 3500 PICKUP: 2007-2011, 2013
SUBURBAN 1500: 2007-2011
SUBURBAN 2500: 2007-2011
TAHOE: 2007-2011
GMC:
SIERRA 1500 PICKUP: 2007-2011
SIERRA 2500 PICKUP: 2007-2011, 2013
SIERRA 3500 PICKUP: 2007-2011, 2013
SIERRA DENALI: 2007-2010
SIERRA DENALI 1500/2500/3500: 2011, 2013
YUKON: 2007-2011
YUKON XL 1500: 2007-2011
YUKON XL 2500: 2007-2011
Cadillac:
ESCALADE: 2007-2011
ESCALADE ESV: 2007-2011
ESCALADE EXT: 2007-2011
Note: For 2007 models, this fits the ‘new style’ with the smooth door skin. Please verify your part number or contact us with your VIN to ensure compatibility.
Frequently Asked Questions
Is this BCM really plug-and-play?
Yes. We program the module to your vehicle’s specific VIN before shipping. This ensures it communicates correctly with your truck’s other systems right out of the box, eliminating the need for expensive dealership programming.
What if my airbag light is on after I install it?
This can happen occasionally. It means the new BCM needs to be electronically introduced to the airbag system (SDM). A mechanic with a professional-grade scan tool can perform the ‘Setup SDM Primary Key in BCM’ procedure in a few minutes to resolve this.
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, which saves you the time and expense of a return shipment.
How can I be sure the BCM is my problem?
The most reliable way is with a proper diagnosis from a qualified technician. However, having multiple, unrelated electrical issues (like windows, locks, and radio all acting up) is a very strong indicator that the BCM, the central hub for these functions, is the culprit.
Will this fix a 2007-2011 Silverado 3500 BCM that is causing a battery drain?
Yes, a failing BCM is a common cause of parasitic battery drain. If the module doesn’t enter ‘sleep mode’ correctly, it can continue to draw power even when the truck is off, leading to a dead battery. Replacing it often solves this issue.