Tired of Your GM SUV’s Electrical Gremlins?
If you’re dealing with flickering lights, power windows with a mind of their own, or strange warning messages on your dash, you’re not alone. The Body Control Module, or BCM, is the central nervous system for your vehicle’s comfort and convenience features. When it starts to fail in vehicles like the Trailblazer or Envoy, it can cause a cascade of frustrating and unpredictable problems. This isn’t just an annoyance; a faulty BCM can affect safety systems and even prevent your vehicle from starting. We offer a reliable, direct-fit solution: a replacement 2002-2004 Trailblazer BCM, professionally programmed to your vehicle’s specific VIN.
Is Your SUV Showing These Symptoms?
- ✔ Power windows, door locks, or interior lights acting erratically or not working at all.
- ✔ The radio or instrument cluster randomly shutting off and turning back on.
- ✔ False warning lights appearing on the dash, such as for the security or 4WD system.
- ✔ Your key fob has stopped working reliably.
- ✔ The vehicle won’t start, despite having a good battery and starter.
- ✔ A mechanic finds communication error codes (like U0140) when scanning the vehicle.
From the Diagnostic Bay: The Case of the Haunted Envoy
A customer brought in their 2003 GMC Envoy, complaining of “ghosts in the machine.” The dome lights would fade on and off while driving, the driver’s window would only work intermittently, and the radio would randomly reset. They had already replaced the battery and checked the grounds. My initial scan showed a dozen intermittent communication codes. In my 20+ years of experience, this pattern almost always points to one component. We located the BCM under the rear seat, and I noticed faint signs of corrosion on one of the connectors—a common issue from moisture. Swapping in a pre-programmed BCM like this one solved every single issue instantly. It’s a classic failure on this platform, and this module is the definitive fix.
The Plug-and-Play Advantage
The biggest hurdle in replacing a BCM is the need for expensive, dealer-level programming. We eliminate that step entirely. Simply provide us with your vehicle’s VIN during checkout, and our technicians will program this module with the latest GM software updates specific to your truck. It arrives at your door ready to be installed, saving you a costly trip to the dealership and significant vehicle downtime. Plus, there is no core charge, so you can keep your original part.
A Straightforward Guide to Installation
- ✔ Step 1: Safety First. Always disconnect the negative battery terminal and wait a few minutes before beginning any work on your vehicle’s electrical system.
- ✔ Step 2: Locate the BCM. On most of these SUVs (Trailblazer, Envoy, etc.), the BCM is part of the rear fuse block assembly, located under the driver’s side rear seat cushion. Lift the cushion to access it.
- ✔ Step 3: Swap the Module. Carefully disconnect the large electrical connectors from the old BCM. Unclip or unbolt the old module and remove it. Position the new, pre-programmed BCM and securely reconnect all wiring harnesses.
- ✔ Step 4: Power Up and Test. Reconnect the negative battery terminal. Turn the key to the ‘On’ position and test all functions: windows, locks, wipers, lights, and radio to ensure proper operation.
- ✔ Step 5: Address Any Warning Lights. In some cases, post-installation procedures may be necessary. If the airbag light is on, an “Airbag System Sync” is required. A “Brake Pedal Position Relearn” may also be needed. These procedures require a professional-grade diagnostic tool.
Will This Fit My SUV?
This BCM is a direct replacement for part number 15114669 and is also compatible with part numbers 15122670, 15065293, 15191621, and 9352135. It fits the following models, specifically those without the factory security system unless noted otherwise:
- Buick Rainier: 2004-2005
- Chevrolet Trailblazer & Trailblazer EXT: 2002-2005
- GMC Envoy, Envoy XL, & Envoy XUV: 2002-2005
- Isuzu Ascender: 2003-2005
- Oldsmobile Bravada: 2002-2004
- Saab 9-7X: 2005
Please note: Always match your original part number or consult your service manual to confirm fitment. This module is for vehicles without the factory security system option.
Frequently Asked Questions
Frequently Asked Questions
What is a Body Control Module (BCM)?
The BCM is a computer in your vehicle that controls non-engine related functions. This includes power windows, locks, interior and exterior lighting, wipers, the security system, and the instrument cluster. It acts as a central hub for these systems.
Is this BCM truly ready to install out of the box?
Yes. We program the module to the VIN you provide before shipping. This ensures it communicates correctly with the other computers in your vehicle, making installation a simple plug-and-play process without needing a trip to the dealer for programming.
Why do you need my Vehicle Identification Number (VIN)?
Your VIN contains specific information about your vehicle’s factory-installed options. Programming the BCM with your VIN ensures all features your vehicle came with will function correctly with the new module.
Do I need to send my old BCM back?
No. We do not require a core return for this part. You can keep your old module, which saves you the time and expense of return shipping.
What are the post-installation relearn procedures?
On some models, after installing the new BCM, the airbag or brake system may need to be recalibrated. This is done with a professional scan tool and ensures safety systems like airbags and traction control function as intended. This is only required if a related warning light appears after installation.