Is Your GM Truck Experiencing Strange Electrical Issues?
If your GMC Sierra, Chevrolet Silverado, or other GM truck or SUV is suddenly acting haunted—with flickering lights, a malfunctioning radio, erratic power windows, or a dead battery—the culprit is often a failing Body Control Module (BCM). The BCM is the central computer for your vehicle’s body electronics, managing everything from the interior lights and door locks to the HVAC system and security features. When it fails, it can cause a cascade of frustrating and difficult-to-diagnose problems.
This genuine GM Body Control Module, interchangeable with part number 20939138 and 25844480, is the definitive solution. We pre-program the module to your vehicle’s specific VIN, ensuring it arrives ready for a true plug-and-play installation. This critical step eliminates the need for an expensive trip to the dealership for programming, saving you time and money and getting your truck back to perfect working order fast.
From the Diagnostic Bay
We had a 2010 Silverado 2500 in the shop that was driving the owner crazy. The battery would be dead every few mornings, the dome lights would stay on intermittently, and the power locks worked only when they wanted to. The owner had already replaced the battery and alternator. After hooking up our scanner, we noticed communication errors with the BCM. A quick check of the main ground under the driver’s side A-pillar showed it was solid. We knew the BCM’s internal circuits were likely failing, causing a parasitic draw. Installing a VIN-programmed BCM like this one solved all the issues in under 15 minutes. The customer was thrilled to have his reliable truck back without the dealership hassle.
Symptoms of a Failing GM Body Control Module
- ✔ Power windows, door locks, or mirrors operating erratically or not at all.
- ✔ Interior or exterior lights staying on, flickering, or failing to turn on.
- ✔ HVAC controls are unresponsive, or the blower motor works intermittently.
- ✔ The vehicle’s security system malfunctions, preventing the engine from starting (PassLock issues).
- ✔ An airbag warning light is illuminated on the dash, often with DTC B1001.
- ✔ Unexplained parasitic battery drain leading to a dead battery.
- ✔ Horn honking unexpectedly or not working when pressed.
Why Choose Our Programmed Sierra 3500 BCM?
This isn’t just a replacement part; it’s a complete, ready-to-install solution. Each module is loaded with the latest GM software updates and configured specifically for your truck’s VIN. This ensures all factory options and systems communicate correctly from the moment you plug it in. The installation is straightforward for any DIYer, typically located under the driver’s side dash near the steering column. While the physical swap takes minutes, be aware that some vehicles may require a post-installation procedure like an ‘SDM Key Sync’ if the airbag light appears. This can be done with most professional-grade scan tools.
This module is a direct replacement for a wide range of part numbers, including: 25835966, 15263363, 15943678, 25790508, 25844479, 20939137, 22860591, and more. Restore your vehicle’s core electronic functions with confidence.
Frequently Asked Questions
What does ‘VIN Programmed’ actually mean?
It means we load the module with your vehicle’s unique 17-digit Vehicle Identification Number (VIN) before shipping. This configures the BCM to work with your truck’s specific features and security system, making it a true plug-and-play part without needing dealer tools.
Do I need to take my truck to a dealer after installing this?
No, in most cases, you will not need to visit a dealer. Our VIN programming handles the primary setup. The only exception is if an airbag light appears, which may require a simple ‘SDM Key Sync’ procedure with a bi-directional scan tool.
Where is the BCM located on my 2008 GMC Sierra 3500?
The BCM is typically located under the driver’s side dashboard, to the left of the steering column. It’s a black plastic box with several large electrical connectors. Access is usually straightforward after removing the lower dash panel.
My airbag light came on after installation. What should I do?
This is a known security feature. You will need to perform the ‘Setup SDM Primary Key in BCM’ procedure using a professional diagnostic tool. This syncs the new BCM with the airbag system’s computer and will turn off the light.
Is there a core charge for this part?
No, there is absolutely no core charge. You can keep your old module without needing to send it back, simplifying the repair process for you.