Fix Your Truck’s Electrical Issues: The Pre-Programmed BCM Solution
If your 2013 Silverado 3500 is plagued by bizarre electrical problems—like the A/C not working, random warning lights, or power windows with a mind of their own—you’ve likely met the common culprit: a failing Body Control Module (BCM). As the central computer for your truck’s comfort and security features, its failure can be incredibly frustrating. This OEM-quality replacement BCM, part number 20939138, is the direct, reliable solution. We pre-program it to your truck’s specific VIN, so it arrives ready for a true plug-and-play installation, eliminating the need for an expensive trip to the dealership.
From the Diagnostic Bay: The Silverado Ghost
I remember a 2011 Sierra 2500 that came into my shop with a laundry list of complaints. The owner said the radio would cut out, the driver’s side window wouldn’t roll down, and the airbag light was on. He’d already replaced the battery and checked fuses. After hooking up my scanner, I saw a dozen communication codes across various modules. In my 20+ years of experience, when you see unrelated systems all acting up, the BCM is the first place to look. It’s the traffic cop for all those electronic signals. We installed a VIN-programmed BCM, and like magic, every single issue was resolved in under an hour. This is a classic failure pattern for these otherwise fantastic trucks.
Is Your GM Truck or SUV Showing These Symptoms?
A faulty BCM can manifest in numerous ways. If you’re experiencing any of the following, a replacement is likely the answer:
- ✔ Your HVAC controls are unresponsive, or the blower motor works intermittently.
- ✔ The airbag warning light is illuminated, often with a DTC like B1001 (Setup SDM Primary Key in BCM).
- ✔ Power accessories like door locks, windows, or interior/exterior lights are failing.
- ✔ The security system is malfunctioning, causing no-start conditions, stalling, or misfires.
- ✔ The vehicle won’t start, but the battery and starter are good (a common security lockout symptom).
- ✔ Multiple, seemingly unrelated diagnostic trouble codes (DTCs) are present.
Your 5-Minute Path to a Fully Functional Truck
Replacing the BCM is a straightforward job that most DIYers can handle with basic tools. This pre-programmed 2013 Silverado 3500 BCM makes the process even simpler. Here’s a general guide:
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before working on any electronics.
- Locate the BCM: On most GM trucks and SUVs from this era, the BCM is located under the driver’s side dashboard, near the steering column. It’s a black box with several large wiring 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 Module: Seat the new, pre-programmed BCM into the bracket and securely plug in all the wiring connectors. You should hear a click as they lock into place.
- Reconnect and Test: Reconnect the battery terminal. Turn the key to the ‘On’ position and test all functions: windows, locks, lights, wipers, and HVAC. Start the vehicle to ensure it runs correctly.
Post-Installation Note: In some cases, particularly if the airbag light was on, you may need a professional scan tool to perform the ‘Setup SDM Primary Key in BCM’ function. A brake pedal position relearn might also be necessary. These are simple procedures for any qualified technician.
Verified to Fit These GM Models
This module is a direct replacement for part number 20939138 and interchanges with several other part numbers (including 25844480, 25835966, 22860591, and more) across a wide range of vehicles:
CHEVROLET SILVERADO 1500/2500/3500 (2007-2013)
CHEVROLET SUBURBAN 1500/2500 (2007-2011)
CHEVROLET TAHOE (2007-2011)
GMC SIERRA 1500/2500/3500 (2007-2013)
GMC SIERRA DENALI (2007-2013)
GMC YUKON & YUKON XL (2007-2011)
CADILLAC ESCALADE, ESV, EXT (2007-2011)
Note: Please verify your specific model and year. Some 2007 models require the ‘new style’ (smooth door skin) body type.
Frequently Asked Questions
Does this BCM really not require a trip to the dealer?
That’s correct. We program the module to your vehicle’s VIN before shipping. This ensures it communicates correctly with your truck’s other systems right out of the box, saving you hundreds in dealership programming fees.
What information do you need from me to program it?
We just need your 17-digit Vehicle Identification Number (VIN). You can typically find this on your driver’s side door jamb sticker or on the dashboard viewable through the windshield. Please provide it during checkout.
Is it difficult to install a 2013 Silverado 3500 BCM?
Not at all. For most people with basic tools, it’s a 5-10 minute job. The module is located under the driver’s side dash and is held in by clips or a few small bolts. Just unplug the old one and plug in the new one.
My airbag light is on. Will this fix it?
If the airbag light is caused by a BCM failure (often DTC B1001), this module will resolve the root cause. However, after installation, the airbag system’s computer (SDM) may need to be synced with the new BCM using a professional scan tool to clear the light.
Do I need to send my old part back?
No, there is no core charge for this part. You can keep or dispose of your old module without any hassle.