Restore Full Control Over Your Truck’s Electronics
Is your GMC Sierra or other GM truck plagued by bizarre electrical issues? As a technician with over two decades of experience, I’ve seen how a failing Body Control Module (BCM) can turn a reliable vehicle into a source of daily frustration. The BCM is the central nervous system for your truck’s comfort and security features. When it malfunctions, you get unpredictable problems that can be a nightmare to diagnose. This VIN-programmed BCM, part number 20939137, is the definitive, hassle-free solution to restore your vehicle’s electronic functions and get you back on the road with confidence.
This isn’t just a part; it’s a permanent fix. We pre-program the module to your vehicle’s specific VIN before shipping, which means it’s ready for a true plug-and-play installation. You can bypass the expensive and time-consuming trip to the dealership for programming. This is the same process we use in the shop to guarantee a seamless repair, ensuring the BCM communicates flawlessly with your truck’s other electronic systems from the moment you connect it.
A Technician’s Notebook: The Grounding Gremlin
A customer brought in a 2012 Silverado with a classic case of BCM failure: intermittent wipers, flickering dash lights, and the radio cutting out. He had already replaced the BCM himself, but the problems returned within a week. During my diagnosis, I found the new BCM was fine. The real culprit? A corroded ground strap near the BCM’s mounting point. In my shop, I’ve seen this dozens of times. A poor ground forces the module to work harder, leading to premature failure. Pro Tip: When you replace your BCM, always take an extra 60 seconds to clean the main BCM ground connection point with a wire brush. It’s the single best thing you can do to ensure your new module lasts for years to come.
Is Your Truck Showing These Symptoms?
A faulty BCM can manifest in numerous ways. If you’re experiencing any of the following, a replacement is likely the solution:
- ✔ Your power windows, door locks, or mirrors work intermittently or not at all.
- ✔ The HVAC system is unresponsive, or the blower motor seems to have a mind of its own.
- ✔ The dreaded airbag warning light is on, often with a DTC like B1001 stored.
- ✔ Your vehicle’s security system is malfunctioning, causing no-start conditions or false alarms.
- ✔ You’re dealing with strange lighting issues, such as headlights or interior lights staying on or not turning on.
- ✔ The instrument cluster displays erratic behavior or warning messages without a clear cause.
A Straightforward Guide to Installation
For most DIYers and professional mechanics, this is a quick and simple job. You’ll have your truck’s electronics working properly in minutes.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before working on any electronic components.
- Locate the BCM: On most compatible GM trucks and SUVs, the Body Control Module is located under the driver’s side of the dashboard, near the steering column.
- Remove the Old Module: Carefully unplug the electrical connectors. They have locking tabs that need to be depressed. Once unplugged, unclip or unbolt the old BCM from its mounting bracket.
- Install the New BCM: Mount your new, pre-programmed module in place and securely reconnect all electrical connectors. Ensure they click into place.
- Reconnect and Test: Reconnect the negative battery terminal. Start the vehicle and test all body functions—lights, windows, locks, HVAC, etc.—to confirm the repair was successful.
- Post-Install Note: In some cases, if the airbag light was on, it may remain on after installation. This requires a professional scan tool to perform the ‘Setup SDM Primary Key in BCM’ function to sync the systems. A Brake Pedal Position Relearn may also be needed on certain models.
Guaranteed Fitment for Your GM Truck or SUV
This module is a direct replacement for part number 20939137 and is interchangeable with a wide range of other GM part numbers, ensuring broad compatibility. It is engineered to fit many popular 2007-2013 General Motors vehicles, including:
- ✔ Chevrolet Silverado 1500, 2500HD, 3500HD
- ✔ GMC Sierra 1500, 2500HD, 3500HD (including Denali)
- ✔ Chevrolet Tahoe & Suburban
- ✔ GMC Yukon & Yukon XL
- ✔ Cadillac Escalade, ESV, EXT
- ✔ Chevrolet Avalanche
This is the ideal solution for anyone needing a 2011 Sierra Denali BCM or a module for any of the other listed vehicles. To ensure perfect fitment, please verify your part number or contact us with your VIN.
Frequently Asked Questions
What does a Body Control Module (BCM) actually do?
The BCM is a computer that controls most of your vehicle’s non-engine related electronic functions. This includes power windows, door locks, the security system, interior and exterior lighting, wipers, and the climate control (HVAC) system.
Will I need to visit a dealership after installing this part?
No. Because we pre-program the module to your VIN, you can skip the dealership’s programming service. In the rare event the airbag light stays on, a ‘Setup SDM Primary Key’ procedure may be needed with a high-end scan tool, which many independent shops can perform.
Is this installation difficult for a DIY mechanic?
Not at all. The BCM is typically easy to access under the dashboard, and the replacement involves simply unplugging the old unit and plugging in the new one. The entire process usually takes less than 15 minutes with basic hand tools.
What does ‘No Core Charge’ mean?
It means you don’t have to send your old, faulty BCM back to us. You can keep it, recycle it, or dispose of it without any extra fees or hassle, simplifying the repair process for you.
How can I be sure this is the right part for my 2011 Sierra Denali BCM replacement?
The best way is to match the part number (20939137) from your original module. This module also replaces many other part numbers listed in the description. If you’re unsure, just send us your vehicle’s VIN, and we’ll verify compatibility for you.