End the Electrical Headaches in Your GM Truck
If you’re dealing with a frustrating array of electrical issues in your GMC Sierra 3500—like power windows with a mind of their own, a dashboard lit up with random warnings, or an HVAC system that’s quit working—you’ve likely met the culprit: a failing Body Control Module (BCM). As a technician with over two decades of experience, I’ve seen how a faulty BCM can turn a reliable truck into a source of constant annoyance. It’s the central hub for your vehicle’s comfort and convenience features, and when it fails, chaos ensues.
This isn’t just another part; it’s the solution. This OEM-quality Body Control Module, corresponding to part number 25835966, is the definitive fix for these widespread problems. We take the biggest hassle out of the repair by pre-programming the module to your truck’s specific Vehicle Identification Number (VIN). This means no expensive trips to the dealership for programming. It’s a true plug-and-play fix designed to get you back on the road with confidence.
A Technician’s Notebook: The Intermittent Gremlin
A customer brought in a 2009 Silverado 2500 (which uses the same BCM platform) with a classic case of electrical gremlins. The radio would cut out, the driver’s side power lock would work one day and not the next, and he had a persistent airbag light. He’d already replaced the battery and checked fuses. After hooking up my scanner, I saw a handful of communication codes. In my shop, I’ve diagnosed hundreds of these GMT900-platform trucks, and I’ve learned that a poor ground connection at the BCM is a common failure point that slowly damages the internal circuitry. We installed a VIN-programmed BCM and ensured the ground point was clean and tight. The problems vanished instantly. This highlights why a quality replacement and proper installation are key.
Is Your Sierra Showing These Electrical Faults?
A failing BCM can manifest in numerous ways. If your truck is experiencing any of the following, a faulty module is the most likely cause:
- ✔ Power windows, door locks, or mirrors operating intermittently or not at all.
- ✔ Interior dome lights or exterior lamps staying on or not turning on.
- ✔ The security system acting erratically, causing no-start or stalling conditions.
- ✔ HVAC controls are unresponsive, or the blower motor works sporadically.
- ✔ An active airbag warning light, often accompanied by Diagnostic Trouble Code (DTC) B1001.
- ✔ A variety of communication (U-codes) or other body-related DTCs stored in the system.
A Straightforward Guide to BCM Replacement
One of the best features of this part is its ease of installation. For most DIYers or any professional mechanic, this is a quick job. You’ll find the BCM located under the driver’s side dashboard, near the steering column.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before beginning any electrical work.
- Locate the Module: Find the BCM under the driver-side dash. It’s typically a black plastic box with several large multi-pin connectors.
- Disconnect and Remove: Carefully unplug the electrical connectors. They have locking tabs that need to be depressed. Once unplugged, unclip or unbolt the old module from its mounting bracket.
- Install the New BCM: Mount your new, VIN-programmed BCM in place and securely reconnect all electrical connectors. You’ll hear a click as they lock in.
- Reconnect and Test: Reconnect the negative battery terminal. Start the vehicle and test all functions: lights, windows, locks, wipers, and HVAC to confirm the repair was successful.
Post-Installation Note: In some cases, particularly if the airbag light was on, you may need to perform a “Setup SDM Primary Key in BCM” procedure using a capable bi-directional scan tool. This re-establishes communication between the new BCM and the airbag system. A brake pedal position relearn might also be necessary on certain models.
Verified Vehicle Compatibility List
This module is a direct replacement for part number 25835966 and other interchangeable numbers. It is guaranteed to fit the following General Motors vehicles. Please verify your model and year.
ESCALADE 07-11
ESCALADE ESV 07-11
ESCALADE EXT 07-11
SIERRA 1500 PICKUP 07-11
SIERRA 2500 PICKUP 07-13
SIERRA 3500 PICKUP 07-13
SIERRA DENALI 07-10
SIERRA DENALI 1500 11
SIERRA DENALI 2500 11-13
SIERRA DENALI 3500 11-13
SILVERADO 1500 PICKUP 07-11
SILVERADO 2500 PICKUP 07-13
SILVERADO 3500 PICKUP 07-13
SUBURBAN 1500 07-11
SUBURBAN 2500 07-11
TAHOE 07-11
YUKON 07-11
YUKON XL 1500 07-11
YUKON XL 2500 07-11
This part is also interchangeable with: 15263363, 15263497, 15878753, 15284816, 15943678, 15926094, 15940214, 25790508, 25790509, 25823558, 25823559, 25835965, 25844479, 25971916, 25971917, 15901388, 20939137, 20939138, 22860591, 25844480.
Frequently Asked Questions
Do I need to send my old BCM back?
No. There is no core charge for this module. You can keep your old part.
Is this part really plug-and-play?
Yes. We program the module to your vehicle’s VIN before shipping, so it’s ready for installation without any additional dealer programming for standard functions.
What if my airbag light stays on after installation?
If the airbag light persists, it simply means the new BCM needs to be synced with the airbag module (SDM). This is done with a professional scan tool using the ‘Setup SDM Primary Key’ function.
Can I install this 2007-2011 Sierra 3500 BCM myself?
Absolutely. With basic hand tools and our installation guide, this is a very manageable job for a DIY enthusiast. It typically takes less than 30 minutes.
What functions does the BCM control?
The Body Control Module manages a wide range of non-engine electronics, including power windows, door locks, interior and exterior lighting, wipers, the security system, and the HVAC blower and mode controls.