Tired of Unpredictable Electrical Problems in Your GM Truck?
If you’re dealing with a 2013 Silverado 3500 that seems to have a mind of its own—with flickering lights, a dead HVAC system, or power windows that won’t budge—the culprit is very likely a failing Body Control Module (BCM). As the electronic nerve center for your truck’s comfort and security features, a faulty BCM can cause a cascade of frustrating issues. This OEM-quality replacement, part number 20939137, is the definitive solution, arriving pre-programmed to your vehicle’s VIN for a hassle-free, plug-and-play installation that gets you back to a reliable ride without a costly trip to the dealership.
Case Study: A Tricky Diagnosis
A customer brought in a 2011 Sierra 2500 with a classic ‘gremlin’ case. The radio would cut out, the driver’s side window worked intermittently, and the airbag light was on with a DTC B1001. They’d already replaced the battery and checked fuses. In my shop, I’ve seen this exact pattern hundreds of times. The BCM is highly susceptible to voltage irregularities, often caused by a poor ground connection at the frame or a failing alternator. After confirming the grounds were solid, we installed a VIN-programmed BCM. The electrical functions were immediately restored. We then used a scanner to perform the ‘Setup SDM Primary Key’ function, which cleared the B1001 code for good. This simple replacement saved the customer from chasing phantom electrical issues for weeks.
Is Your Truck Showing These Symptoms?
- ✔ The security light is flashing and the engine stalls or refuses to start.
- ✔ Power windows, door locks, or interior lights work sporadically or not at all.
- ✔ The HVAC blower motor is inoperative or stuck on one speed.
- ✔ An airbag warning light is illuminated, often with a persistent DTC B1001 code.
- ✔ Strange electrical behavior, like the horn honking or wipers activating on their own.
- ✔ Communication errors with other modules on the CAN bus network.
A Straightforward Guide to Installation
Replacing your 2013 Silverado 3500 BCM is a job most DIYers can complete in under 10 minutes. The module is typically located under the driver’s side dashboard, near the steering column.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- Locate the BCM: On most GM trucks of this era, you’ll find it mounted to a bracket just above the driver’s left foot area. It’s a black box with several large multi-pin connectors.
- Disconnect and Remove: Carefully unplug all electrical connectors. They have locking tabs that need to be depressed. Once disconnected, unclip or unbolt the old module from its mounting bracket.
- Install the New Module: Snap the new, VIN-programmed BCM into place and securely reconnect all the wiring harnesses. You should hear a ‘click’ as they lock.
- Reconnect and Test: Reconnect the negative battery terminal. Turn the key to the ‘On’ position and test all functions: lights, locks, windows, wipers, and the HVAC system.
- Post-Installation Steps: In some cases, an airbag light may remain on. This requires a diagnostic scan tool with special functions to perform the ‘Setup SDM Primary Key in BCM’ procedure. A ‘Brake Pedal Position Relearn’ may also be necessary on certain models.
Verified Vehicle Compatibility
This module is a direct-fit replacement for a wide range of General Motors trucks and SUVs. It is interchangeable with part numbers 25844480, 25835966, 15901388, 20939138, 22860591, and more. While this is a perfect fit for a 2013 Silverado 3500 BCM repair, please verify your specific model in the list below:
CADILLAC ESCALADE, ESV, EXT 07-11
CHEVROLET SILVERADO 1500/2500/3500 PICKUP 07-13
CHEVROLET SUBURBAN 1500/2500 07-11
CHEVROLET TAHOE 07-11
GMC SIERRA 1500/2500/3500 PICKUP 07-13
GMC SIERRA DENALI 07-13
GMC YUKON & YUKON XL 07-11
Note: For 2007 models, this fits the ‘New Style’ with a smooth door skin. For some 2010 and 2013 models, please confirm ID 25835966 on your original part.
Frequently Asked Questions
What exactly does a Body Control Module do?
The BCM is a computer that acts as the central hub for your vehicle’s body electronics. It controls non-engine related functions like power windows, door locks, the security system, interior and exterior lighting, wipers, and the climate control system.
Why is VIN programming so important?
VIN programming loads your vehicle’s specific software and settings onto the BCM. This ensures all features your truck was built with work correctly right out of the box. Without it, you would face a costly and time-consuming trip to a dealership for programming.
Do I need a special scan tool after installation?
For most functions, no. The module is plug-and-play. However, if your airbag light was on (DTC B1001) or comes on after install, you will need a bi-directional scan tool to perform the ‘Setup SDM Primary Key in BCM’ procedure to sync the airbag system.
Is there a core charge for my old part?
No, there is absolutely no core charge. You can keep your old module without any hassle or need to return it.
What kind of warranty is included?
This part is backed by our standard one-year warranty, giving you peace of mind and confidence in your repair.