Is Your GM SUV Plagued by Electrical Gremlins?
If you’re dealing with flickering lights, malfunctioning power windows, or a battery that mysteriously drains overnight in your GMC Envoy, Chevy Trailblazer, or other GMT360 platform SUV, a failing Body Control Module (BCM) is the most likely culprit. The BCM is the central command center for your vehicle’s body electronics, and when it starts to fail, it can cause a cascade of frustrating and seemingly unrelated issues. This isn’t just a component; it’s the solution to restoring your vehicle’s functionality and your peace of mind.
From the Diagnostic Bay
We recently had a 2004 Trailblazer in the shop with a classic ‘my battery is always dead’ complaint. The owner had already replaced the battery twice and even the alternator, with no success. After a quick parasitic draw test, we traced the power drain to the interior lighting circuit. The BCM was failing to put the circuit to sleep, keeping the lights on at a very low, almost unnoticeable level, but enough to drain the battery in 12 hours. A pre-programmed Envoy BCM Replacement like this one solved a problem that had cost the owner hundreds in unnecessary parts and diagnostic fees.
Symptoms of a Failing BCM
- ✔ Power windows, door locks, or mirrors working intermittently or not at all.
- ✔ Interior dome lights staying on, flickering, or refusing to turn on.
- ✔ Headlights, taillights, or turn signals behaving erratically.
- ✔ The security system engaging randomly or not working correctly.
- ✔ Unexplained warning lights on the instrument cluster.
- ✔ A persistent parasitic battery drain that kills your battery when parked.
- ✔ Radio or climate control malfunctions.
The Plug-and-Play Solution, Programmed for Your SUV
Don’t waste time and money at a dealership. We provide a fully tested, genuine OEM Body Control Module that is programmed specifically to your vehicle’s Vehicle Identification Number (VIN) before it ships. This means no expensive programming tools or trips to a mechanic are required for the initial setup. The module arrives ready to be installed, communicating perfectly with the other computers in your vehicle right out of the box.
Installation and Post-Install Procedures
Installation is straightforward for a DIYer with basic tools. The BCM is typically located in or near the front fuse box area. After physically installing the module, you’re almost done. However, on some vehicles, a couple of simple relearn procedures may be necessary to sync all systems perfectly.
- Airbag System Sync: If your airbag warning light is on after installation, a ‘Setup SDM Primary Key in BCM’ procedure is needed. This requires a professional scan tool to sync the new BCM with the airbag system. This is only necessary if the light appears.
- Brake Pedal Position Relearn: To ensure your brake lights and traction control system function correctly, a brake pedal position sensor recalibration might be required. This can also be performed with a compatible diagnostic tool.
This Envoy BCM Replacement is a direct fit for part numbers 15065293, 15122670, 15114669, 15191621, and 9352135, and fits a wide range of GM SUVs from 2002-2005, including the Trailblazer, Rainier, Bravada, Ascender, and Saab 9-7X. Please verify the part number and check the detailed fitment list to ensure compatibility.
Frequently Asked Questions
What is a BCM and what does it do?
The Body Control Module (BCM) is a computer in your vehicle that manages and controls all the electronic accessories related to the vehicle’s body, such as power windows, locks, lights, wipers, and the security system.
Is this BCM difficult to install?
The physical installation is typically simple, involving unplugging the old module and plugging in the new one. As this unit comes pre-programmed to your VIN, it eliminates the most difficult step. Some models may require post-install sync procedures as detailed above.
How do I provide my VIN for programming?
After you complete your purchase, you will need to send us your 17-digit VIN. We cannot ship your order until we receive this information, as the programming is essential for the part to function in your vehicle.
Do I need to send my old BCM back?
No, there is no core charge for this part. You can keep your original module.
What happens if my airbag light comes on after installation?
This indicates the new BCM needs to be synced with the airbag system’s computer (SDM). A mechanic with a professional-grade scan tool will need to perform the ‘Setup SDM Primary Key in BCM’ procedure to resolve this.
Will this part fit my 2003 Chevy Trailblazer?
Yes, this BCM is compatible with a wide range of 2002-2005 GM SUVs built on the GMT360 platform, including the Trailblazer, Envoy, Rainier, Bravada, and more. Please cross-reference your original part number with our list (15065293, 15122670, etc.) to confirm.