Are you dealing with baffling electrical issues in your Buick Rainier or other GM SUV? One moment the power windows work, the next they don’t. Maybe your dashboard lights are flickering like a disco ball, or the vehicle refuses to start intermittently. As a technician with over two decades of experience, I’ve seen these exact symptoms hundreds of time, and they almost always point to a failing Body Control Module (BCM). This isn’t just an annoyance; a faulty BCM can affect everything from your interior lights and radio to critical systems like anti-theft and brake light activation, making it a serious safety concern.
The BCM is the central nervous system for your vehicle’s body electronics. When it fails, communication between different components breaks down, leading to the chaotic and unpredictable problems you’re likely experiencing. Traditionally, replacing it meant a trip to the dealership for expensive parts and even more expensive programming. We solve that problem. This listing is for a replacement BCM with our expert Cloning Service. You send us your original module, and we transfer all its vital data—including key information and vehicle-specific settings—to this replacement unit. The result? A true plug-and-play solution that gets you back on the road without the dealership hassle.
A Technician’s Notebook
I remember a 2006 Trailblazer that came into my bay with the weirdest collection of symptoms. The owner said his radio would switch stations on its own, the dome light wouldn’t turn off, and his power locks had a mind of their own. He had already replaced the battery and checked all the fuses. After hooking up my scan tool, I saw multiple U-codes (communication errors) pointing to the BCM. Instead of a costly new unit from the dealer, we used a cloned module. Once installed, every single one of those ghost-in-the-machine problems vanished. It’s a textbook BCM failure for this platform, and this cloned module is the most effective fix I’ve found.
Common Signs of a Failing BCM
- ✔ Erratic or non-functional power windows, door locks, and interior/exterior lights.
- ✔ The security or anti-theft light stays on, preventing the engine from starting.
- ✔ Dashboard warning lights illuminate randomly.
- ✔ The radio or climate control system behaves unpredictably or doesn’t work at all.
- ✔ Diagnostic trouble codes (DTCs) related to communication loss, such as U0140, U0155, or other U-codes.
- ✔ Rapid battery drain while the vehicle is off.
Your Straightforward Installation Guide
- ✔ Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- ✔ Locate the BCM: On most of these GM SUVs, the BCM is part of the front fuse box assembly, typically located under the rear seat on the driver’s side.
- ✔ Remove the Old Module: Carefully disconnect all electrical connectors leading to the BCM. They have locking tabs that need to be depressed. Once disconnected, unbolt or unclip the module from its mounting location.
- ✔ Install the New Module: Seat your newly programmed BCM in the same position and secure it. Reconnect all electrical connectors, ensuring they click firmly into place.
- ✔ Reconnect Power: Reattach the negative battery terminal and tighten it securely.
- ✔ Test Functionality: Start the vehicle and test all body functions—windows, locks, lights, radio, etc.—to confirm the repair. Note the post-installation procedures below.
Important Post-Installation Steps
While our cloning service makes this a plug-and-play repair, some vehicle systems may require a handshake with the new BCM. Please be aware of the following:
- Airbag System Sync: If your airbag warning light is on after installation, a simple ‘Setup SDM Primary Key in BCM’ procedure is needed. This requires a professional-grade scan tool to sync the modules and clear the light.
- Brake Pedal Position Relearn: On some models, a brake pedal position sensor relearn may be necessary to ensure correct brake light and traction control operation.
Disclaimer: Vehicle systems can vary. We always recommend consulting a factory service manual or a certified technician if you are unsure about any step.
Verified Vehicle Compatibility
This BCM is a direct replacement for part numbers 15135466, 25802312, 8258023120, and 15787809 and fits the following models:
- 2005-2007 Buick Rainier (Body Control, front, w/o security system)
- 2005-2009 Chevrolet Trailblazer (Body Control, front, w/o security system)
- 2005-2006 Chevrolet Trailblazer EXT (Body Control, front, w/o security system)
- 2005-2009 GMC Envoy (Body Control, front, w/o security system)
- 2005-2006 GMC Envoy XL (Body Control, front, w/o security system)
- 2005-2008 Isuzu Ascender (Body Control, front, w/o security system for 05-07)
- 2006-2009 Saab 9-7X (Body Control, front)
Frequently Asked Questions
What is the ‘Cloning Service’?
Cloning is a process where we transfer the essential configuration data from your original, failing BCM directly to this replacement unit. This includes VIN, mileage, and key data, which allows the module to work in your vehicle without any additional programming from a dealer.
Do I need to send my original BCM to you?
Yes. For the cloning service to work, we need your original module. After you place your order, we will provide instructions on where to send it. We will return your original module with your newly programmed replacement.
Will this fix my no-start problem?
If your no-start issue is caused by the BCM’s anti-theft function failing (a very common issue), then yes, this cloned module will resolve the problem by restoring the correct key data.
Is this part difficult to install for a DIYer?
The physical replacement is straightforward for someone with basic mechanical skills. It’s typically located under the rear seat and involves disconnecting connectors and a few bolts. The main benefit of our service is eliminating the difficult and expensive software programming step.
What if my airbag light comes on after installation?
This is not uncommon. It simply means the new BCM needs to be electronically introduced to the airbag module (SDM). A mechanic with a bi-directional scan tool can perform the ‘Setup SDM Primary Key in BCM’ procedure in a few minutes to resolve this.
Which part numbers does this BCM replace?
This module is a direct replacement for several part numbers, including 15135466, 25802312, 8258023120, and 15787809. As long as your vehicle is on the compatibility list, this part will work for you.