Important: Never swap OnStar® vehicle integration units (VIU), or the 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 10-digit specific station identification (STID) and the VCU has a 11-digit 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 left side trim from the rear compartment.
2. Remove the spare tire.
3. Remove the VCU (1) and the bolts, including the electrical connection, from the side trim assembly of the rear compartment.



4. Slide the long end cap (1) P/N 093666841, over the end of the VCU with the connectors. Slide the short end cap P/N 093666831, over the opposite end.
5. The old VCU must be returned for core credit.

1. Record the 11-digit ESN from the label on the new VCU module.



2. Install the VCU (1) and the bolts including the electrical connection.
3. Install the spare tire.
4. Install the left side trim to the rear compartment.
5. Reconfigure the OnStar® system. Refer to OnStar Reconfiguration .

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