Restore Full Electrical Function to Your GM SUV
Are you battling bizarre electrical problems in your Trailblazer, Envoy, or Rainier? Flickering lights, unresponsive power windows, a malfunctioning security system, or random warning messages on the dash are classic signs of a failing Body Control Module (BCM). This central computer governs dozens of comfort and convenience features, and when it fails, it can make your vehicle incredibly frustrating to drive. We offer a straightforward, reliable solution: a replacement BCM, professionally programmed to your vehicle’s specific VIN with the latest GM software updates before it ever leaves our facility. This eliminates the need for an expensive trip to the dealership for programming.
We had a 2006 GMC Envoy come into the shop where the owner had already replaced both front window motors and switches, but the windows still wouldn’t work. He was convinced the wiring was bad. After a quick scan, we saw no communication from the BCM to the driver’s door module. Instead of a costly and time-consuming wiring chase, we identified the BCM as the root cause. A new, programmed BCM had his windows working perfectly in minutes. It’s a classic case of symptoms in one area being caused by the central computer.
Common Symptoms of a Failing BCM
- ✔ Power windows, locks, or mirrors working intermittently or not at all.
- ✔ Interior or exterior lights behaving erratically (staying on, not turning on, flickering).
- ✔ The security system or keyless entry malfunctioning.
- ✔ False warnings on the instrument cluster (e.g., “Service 4WD”).
- ✔ HVAC (heating and air conditioning) controls not responding correctly.
- ✔ Radio or entertainment system issues.
- ✔ Communication errors with other modules when scanned with a diagnostic tool.
The Simple, VIN-Programmed Solution
Forget about the hassle and high cost of dealership programming. Our process is designed for a seamless repair. You provide us with your vehicle’s VIN during checkout, and we handle the complex part. We flash a quality replacement module with the latest GM-certified software that is specific to your truck’s build. This ensures all factory-installed options are recognized and function correctly right out of the box. When you receive the module, it’s ready for a direct installation.
Your 2005-2006 Trailblazer EXT BCM Installation Guide
Physically installing the BCM is typically a straightforward process, as it is located with the front fuse box. After the new module is connected, your vehicle may require one or more simple relearn procedures to ensure all systems communicate properly. Please be aware of the following potential post-installation steps:
- Airbag System Sync: The BCM and the SDM (Sensing and Diagnostic Module, or airbag module) communicate with each other for safety. If the airbag warning light is illuminated after installation, it means this handshake needs to be re-established. A professional scan tool is required to perform the “Setup SDM Primary Key in BCM” procedure to sync the system and turn off the light.
- Brake Pedal Position Relearn: To ensure proper brake light function and stability/traction control performance, a brake pedal position sensor recalibration may be necessary on some models.
Disclaimer: Specific procedures can vary by vehicle. Always consult a factory service manual or a qualified technician for guidance.
Guaranteed Fitment & Part Number Compatibility
This BCM is a direct replacement for the following part numbers:
15135466, 25802312, 8258023120, 15787809
It is programmed to fit the following vehicles (without security system option where noted):
- 2005-2009 Chevrolet Trailblazer
- 2005-2006 Chevrolet Trailblazer EXT
- 2005-2009 GMC Envoy
- 2005-2006 GMC Envoy XL
- 2005-2007 Buick Rainier
- 2005-2008 Isuzu Ascender
- 2006-2009 Saab 9-7X
Frequently Asked Questions
What is a BCM and what does it do?
The Body Control Module (BCM) is a central computer in your vehicle that manages a wide range of non-engine related functions. This includes power windows, door locks, interior and exterior lighting, the security system, and HVAC controls.
Is this BCM truly plug-and-play?
It is pre-programmed to your vehicle’s VIN for a direct installation, which handles the most complex part of the job. However, some vehicles may require a simple relearn procedure for the airbag or brake systems after installation, which may require a professional scan tool.
Why do you need my VIN?
Your vehicle’s 17-digit VIN (Vehicle Identification Number) allows us to load the exact software and settings your vehicle was built with at the factory. This ensures all your specific options, like power seats or keyless entry, work correctly.
What happens if my airbag light comes on after installation?
This indicates the BCM and the airbag module (SDM) need to be electronically synced. A qualified technician with a capable scan tool can perform the ‘Setup SDM Primary Key in BCM’ procedure to resolve this and turn off the light.
Do I need to send my old BCM back?
No. This product comes with no core charge, so you can keep your original module.
Will this fix my specific electrical problem?
This module will correct issues directly caused by a faulty BCM. It is crucial to properly diagnose the problem first, as similar symptoms can also stem from bad wiring, faulty switches, or other modules.