Important: Never swap OnStar® vehicle integration units (VIU) or vehicle communication units (VCU) from other vehicles. Transfer of OnStar® components from other vehicles should not be done. Each OnStar® component has a unique identification number. The VIU has a specific station identification (STID) and the VCU has a specific electronic serial number (ESN). These identification numbers are used by the National Cellular Telephone Network and OnStar® systems, and are stored in the General Motors vehicle history files by VIN.

1. Remove the storage compartment. Refer to Instrument Panel Storage Compartment Replacement .
2. Disconnect the vehicle body harness from the VIU bracket.
3. Disconnect the VIU electrical connector (3) from the OnStar® harness.
4. Disconnect the cell antenna coaxial cable (1) from the VCU.
5. Disconnect the VCU electrical connector from the VCU.



6. Disconnect the VCU from the VIU bracket.
7. Remove the VCU from the vehicle.



8. Disconnect the 2 electrical connectors red (4), blue (3) from the VIU (1).
9. Disconnect the global position sensor (GPS) antenna from the VIU.
10. Disconnect the electrical connector (2) from the underside of the VIU bracket.



11. Remove the 3 J-nuts that secure the VIU bracket.
12. Remove the 3 screws from the HVAC blower motor housing.
13. Remove the VIU from the vehicle.
14. The old VIU or VCU must be returned for core credit.

1. If you are replacing the VIU or the VCU you need to record the following numbers:

•	If you are replacing the VIU, record the 10-digit STID number from the label on the new VIU module.

•	If you are replacing the VCU, record the 11-digit ESN from the label on the new VCU module.

Notice: Refer to Fastener Notice in the Preface section.




2. Install the 3 screws into the screw bosses on the HVAC blower motor housing.

Tighten
Tighten the screws to 3 N·m (2 lb in).

3. Slide the 3 J-nuts into place on the VIU bracket.
4. Connect the electrical connector to the underside of the VIU bracket.



5. Connect the GPS antenna cable to the VIU (1).
6. Connect the 2 electrical connectors red (4), blue (3) from the OnStar® harness to the VIU (1).



7. Connect the VCU to the VIU bracket.



8. Connect the black electrical connector (4) to the VCU.
9. Connect the cell antenna coaxial cable (1) to the VCU.
10. Locate the 4-way prewired audio jumper harness. This harness is taped to the metal crossbar in the storage compartment cavity. Pull the tape to release the connector.
11. Connect the 4-way connector (3) to the OnStar® harness.
12. Locate the vehicle body harness and secure the harness to the VIU bracket (2).
13. Reinstall the storage compartment.
14. If you replace the modules, or the power was disconnected, reconfigure the module. Refer to OnStar Reconfiguration .

The 11-digit ESN number will be needed by the OnStar® advisor.