For 1990-2009 cars only
Removal Procedure
- Open the rear compartment lid.
- Remove the seat back trim panel. Refer to Rear Compartment Front Trim Panel Replacement .
- Remove the 4 nuts (1) securing the module bracket assembly (2) to the rear seat back panel (3).
- Lower the module bracket assembly into the rear compartment.
- Disconnect the cellular coaxial cable from the VCU by pulling upward on the spring loaded snap connector.
- Disconnect the electrical connector.
- Remove the OnStar® VCU by lifting the retainer tab.
- Remove the VCU.
- The old VCU must be returned for core credit.
Important: The vehicle communication unit (VCU) has a specific set of unique numbers that tie the module to each vehicle. These numbers, the 10-digit station identification and the 11-digit electronic serial number, are used by the National Cellular Network and OnStar® to identify the specific vehicle. Because these numbers are tied to the vehicle identification number of the vehicle, you must never exchange these parts with those of another vehicle.
Installation Procedure
- Record the 11-digit ESN from the label on the new VCU module.
- Install the OnStar® VCU to the module bracket assembly.
- Ensure the locking tab is secure to the VCU.
- Connect the electrical connector.
- Connect the cellular coaxial cable to the VCU until fully seated.
- Install the module bracket assembly (2) to the seat back panel (3).
- Install the nuts (1).
- Install the seat back trim. Refer to Rear Compartment Front Trim Panel Replacement .
- Close the rear compartment lid.
- Reconfigure the OnStar® system. Refer to OnStar Reconfiguration .
- Return the old VCU for core credit.
Notice: Refer to Fastener Notice in the Preface section.
Tighten
Tighten the nuts to 9 N·m (80 lb in).
Important: After replacing the VCU, you must reconfigure the OnStar® system. Failure to reconfigure the system will result in an additional customer visit for repair.
