Are you chasing down bizarre electrical issues in your GMC Envoy or similar GM SUV? One minute the power windows work, the next they don’t. Maybe the interior lights have a mind of their own, or the radio cuts out unexpectedly. As a technician with over two decades of experience, I’ve seen these exact symptoms hundreds of times, and they almost always point to a failing Body Control Module (BCM). This isn’t just an annoyance; it’s the central command center for your vehicle’s comfort and convenience features. When it fails, your reliable SUV can become a source of daily frustration.
This is your direct-fit, permanent solution. We offer a replacement BCM, part number 15114669, that arrives at your door programmed to your vehicle’s specific VIN. This means we load the latest GM software onto the module before we ship it. You get a component that is ready for installation, eliminating the need for an expensive trip to the dealership for programming. It’s the most efficient way to restore full functionality and get your truck back to normal.
Case Study: A Tricky Diagnosis
A 2004 Trailblazer came into my shop last month with a laundry list of complaints from the owner: the horn would honk randomly, the rear wiper wouldn’t turn off, and the power locks were intermittent. He had already replaced the battery and checked all the fuses. After connecting my diagnostic scanner, I saw multiple communication error codes (U-codes) pointing to the BCM. The internal circuitry, specifically the relays controlling these functions, had failed from years of heat cycles and vibration. We installed a VIN-programmed 2002-2005 Envoy BCM like this one, and within an hour, every single issue was resolved. The customer was thrilled to have his truck back without the gremlins.
Common Signs of a Failing BCM
- ✔ Erratic power window or door lock operation.
- ✔ Interior or exterior lights staying on or not turning on at all.
- ✔ The security or anti-theft light flashing, preventing the engine from starting.
- ✔ Malfunctioning radio, climate controls, or instrument cluster gauges.
- ✔ The horn sounding unexpectedly or not working when pressed.
- ✔ Wipers operating intermittently or not parking in the correct position.
- ✔ Diagnostic trouble codes (DTCs) related to communication loss, such as U0140, U0155, or various B-codes.
A Straightforward Guide to Your BCM Installation
- ✔ Safety First: Disconnect the negative terminal from your vehicle’s battery and wait a few minutes for the system to fully discharge.
- ✔ Locate the BCM: On most of these GM SUVs, the BCM is part of the interior fuse box assembly, typically located under the rear seat on the driver’s side. In the Envoy XUV, it may be under the rear floor panel. Always confirm the location for your specific model.
- ✔ Access the Module: You may need to remove a trim panel or lift the rear seat cushion to get clear access to the fuse box/BCM assembly.
- ✔ Disconnect and Remove: Carefully unplug all the electrical connectors from the old BCM. They have locking tabs that need to be depressed. Once disconnected, unbolt or unclip the module from its mounting location.
- ✔ Install the New BCM: Mount your new, pre-programmed BCM in the exact same position. Securely plug in all the electrical connectors, ensuring each one clicks firmly into place.
- ✔ Reconnect and Test: Reconnect the negative battery terminal. Turn the key to the ‘On’ position (without starting the engine) and test all body functions: windows, locks, lights, wipers, and radio.
Important Post-Installation Notes
Your new 2002-2005 Envoy BCM is designed for a simple installation, but some vehicles may require a final sync procedure. Don’t worry, this is straightforward.
- Airbag System Sync: If, and only if, the airbag warning light is on after installation, a simple ‘Setup SDM Primary Key in BCM’ procedure is needed. This syncs the new BCM with the airbag module and requires a professional scan tool.
- Brake Pedal Position Relearn: On some models, a brake pedal position sensor recalibration might be necessary to ensure brake lights and traction control work perfectly. This is also performed with a capable scan tool.
And remember, we have a No Core Charge policy. You can keep your old module, saving you the time and hassle of a return shipment.
Verified Vehicle Compatibility
This module is a guaranteed fit for the following vehicles, replacing part numbers 15122670, 15065293, 15114669, 15191621, and 9352135. Please note the specific options for your model.
- Buick Rainier: 2004-2005 (w/o security system)
- Chevrolet Trailblazer & Trailblazer EXT: 2002-2005 (Most models w/o security system)
- GMC Envoy, Envoy XL, Envoy XUV: 2002-2005 (Most models w/o security system)
- Isuzu Ascender: 2003-2005 (w/o security system)
- Oldsmobile Bravada: 2002-2004 (w/o security system)
- Saab 9-7X: 2005
Frequently Asked Questions
Do I need to send you my old BCM?
No. This purchase comes with no core charge. You can keep your original part, which saves you the cost and effort of shipping it back.
What is VIN programming and why do I need it?
VIN programming involves loading your vehicle’s specific software and settings onto the BCM before we ship it. This makes the module communicate correctly with your truck’s other systems, allowing for a much simpler, plug-and-play style installation without a trip to the dealer.
How do I provide my VIN?
After you complete your purchase, you will receive instructions on how to send us your vehicle’s 17-digit VIN. We cannot ship your part until we receive this information.
Will this fix my ‘Service 4WD’ light?
While the BCM communicates with many systems, a ‘Service 4WD’ light is more commonly caused by a faulty Transfer Case Control Module (TCCM) or the front axle actuator on these platforms. It’s best to diagnose that issue separately.
What tools are needed for the post-installation procedures?
The Airbag System Sync and Brake Pedal Position Relearn, if needed, require a bi-directional professional diagnostic tool like a Snap-on Solus, Autel MaxiSYS, or a GM Tech 2. Most local repair shops have this equipment.