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 VIU (1) and the bolts, including the electrical connection, from the side trim assembly of the rear compartment.



4. The VIU is attached with L-brackets (1) which are screwed into the VIU unit, P/N 20472183. You can identify the VIU by the small, flat, and shiny metal case.
5. The old VIU must be returned for core credit.

1. Record the 10-digit STID number from the label on the VIU module.

Notice: Refer to Fastener Notice in the Preface section.

2. Install the VIU (1) and the bolts, including the electrical connection.

Tighten
Tighten the bolts to 0.2 N·m (1.6 lb in).

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 10-digit STID number recorded will be needed by the OnStar® Dealer Support line.