Is Your GM SUV Acting Possessed? It’s Probably the BCM.
If your 2002-2005 Trailblazer, Envoy, Rainier, or Bravada is suffering from a case of electrical gremlins, you’ve come to the right place. Flickering lights, power windows with a mind of their own, intermittent wipers, or a security light that won’t turn off are all classic signs of a failing Body Control Module (BCM). This module is the central nervous system for your vehicle’s body electronics, and when it starts to fail, it can cause a cascade of frustrating and unpredictable problems. Don’t replace expensive components like window motors or light switches until you’ve considered the root cause.
From the Diagnostic Bay
We had a 2004 GMC Envoy come in that was driving the owner crazy. The dome lights would randomly turn on while driving, the radio would lose power, and the power locks worked only when they felt like it. The owner had already replaced the battery and had the alternator tested twice. After plugging in our scan tool, we saw multiple communication loss codes with various accessory modules. This pointed us directly to the BCM. A quick swap with a pre-programmed unit like this one, and the Envoy was back to normal. It’s a common failure point on this platform, and a proper Trailblazer BCM Replacement is often the only permanent fix.
Symptoms of a Failing BCM
- ✔ Intermittent or non-functional power windows, locks, or mirrors.
- ✔ Erratic interior or exterior lighting behavior (flickering, staying on, or not working at all).
- ✔ Wipers operating randomly or not responding to the switch.
- ✔ Horn honking unexpectedly or not working.
- ✔ False security system alarms or a persistent security warning light.
- ✔ Issues with the radio or climate control functions.
- ✔ Communication error codes (U-codes) when scanned with a diagnostic tool.
The Direct-Fit, Programmed Solution
Forget the hassle and expense of a dealership visit. This Body Control Module is a direct replacement for your original part and comes fully programmed to your vehicle’s specific Vehicle Identification Number (VIN). We install the latest, most stable software updates from GM, ensuring optimal performance and compatibility. This plug-and-play approach eliminates the need for expensive dealer-specific tools for programming. Just provide us with your VIN during checkout, and we’ll handle the rest. This is the simplest and most effective Trailblazer BCM Replacement available.
Installation & Post-Install Notes
This BCM is typically located on the front fuse box. While the physical installation is straightforward for a DIYer with basic tools, some post-installation procedures may be necessary depending on your specific vehicle. Please be aware of the following:
- Airbag System Sync: If your airbag warning light is illuminated after installation, a ‘Setup SDM Primary Key in BCM’ procedure must be performed. This requires a professional-grade scan tool to sync the new BCM with the airbag system.
- Brake Pedal Position Relearn: In some cases, a brake pedal position sensor recalibration may be needed to ensure correct brake light operation and traction control functionality.
We make the process easy with no core charge. You can keep your old module without the hassle of shipping it back.
Guaranteed Fitment for Part Number 15122670
This module is a direct replacement for the following part numbers: 15122670, 15065293, 15114669, 15191621, and 9352135. It fits a wide range of 2002-2005 GM SUVs, including the Chevrolet Trailblazer, GMC Envoy, Oldsmobile Bravada, Buick Rainier, Isuzu Ascender, and Saab 9-7X. Please verify your part number and check the fitment list to ensure compatibility.
Frequently Asked Questions
Do I need to get this BCM programmed?
No. We handle all the programming for you before we ship the part. Simply provide your vehicle’s VIN at checkout, and it will arrive ready for installation.
What is a BCM and what does it do?
The Body Control Module (BCM) is a computer that manages and controls many of your vehicle’s non-engine related electronic functions, such as power windows, locks, lights, wipers, and the security system.
Where is the BCM located on my Trailblazer or Envoy?
On most of these models, the BCM is integrated into or attached to the side of the interior fuse box, typically located under the driver’s side of the dashboard or under the rear seat.
Why is my airbag light on after installing the new BCM?
The new BCM needs to be electronically ‘introduced’ to the vehicle’s airbag module (SDM). This requires a ‘Setup SDM Primary Key’ procedure with a compatible high-end scan tool to sync the components and turn off the light.
Is there a core charge for this part?
No, there is no core charge. You are not required to send your old, faulty module back to us.