TrailBlazer 4WD V8-6.0L (2007)
Central Control Module: Service and Repair
Communication Interface Module Replacement (TrailBlazer EXT, Envoy XL)
Communication Interface Module Replacement (TrailBlazer EXT, Envoy XL)
Removal Procedure
Important: Do not exchange the vehicle communication interface module with other vehicles. Each vehicle communication interface
module has a specific station identification (STID) and electronic serial number (ESN). These identification numbers are stored in the
General Motors vehicle history files by VIN and used by OnStar(R) and the National Cellular Telephone Network.
1. Fold and tumble the right second row seat to a cargo position.
2. Remove the protective cover (1) from the vehicle communication interface module (VCIM).
3. Remove the VCIM from the bracket by releasing the retaining tab (1).
4. Remove the electrical connectors from the VCIM.
5. Remove the VCIM from the vehicle.
Installation Procedure
1. If replacing the VCIM, record the 10-digit STID number, and the 11-digit ESN number from the labels on the new module.
2. Position the VCIM near the mounting location.
3. Install the quick connector to the VCIM.