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 rear compartment trim. Refer to Rear Compartment Trim Panel Replacement .
2. Remove the electrical component mounting bracket nuts (2).
3. Pull the electrical component mounting bracket (1) away from the body and place the electrical component mounting bracket  (1) module side up in the rear compartment.



4. Remove the VCU/VIU from the electrical component mounting bracket. Release the module retaining tab, and pull the VCU/VIU up and out of the lower section of the electrical component mounting bracket (1).



5. Remove the VIU/VCU modules (2) from the electrical component mounting bracket (1).
6. Disconnect the antenna and the electrical connections from the VCU/VIU assembly (2).



7. Slide the VCU/VIU assembly (2) out of the mounting bracket (1).



8. Remove the screws retaining the VCU mounting bracket (1) to the VIU (2).
9. Remove the mounting bracket (1) from the VIU (2).
10. The old VIU must be returned for core credit.

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



2. Install the VCU mounting bracket (1) to the VIU (2).

Notice: Refer to Fastener Notice in the Preface section.

3. Install the screws in order to secure the mounting bracket (1) to the VIU (2).

Tighten
Tighten the screws to 2 N·m (18 lb in)




4. Install the VCU (2) to the VIU and bracket assembly (1).




Notice: In order to avoid damage to the circuit board, do NOT over-tighten the thumb screws. Using your fingers, apply only a light pressure.

5. Connect the electrical connector.

Apply 0.2 N·m (2 lb in) of torque, or less, to the VIU thumb screw electrical connections.

6. Install the VIU/VCU (2) to the electrical component mounting bracket (1).



7. Push in on the top of the module assembly until an audible click is heard. This click indicates the mounting tab (1) has securely fastened the VIU/VCU to the electrical component mounting bracket.
8. Install the electrical component mounting bracket (1) to the vehicle body.



9. Install the electrical component mounting bracket nuts (2).

Tighten
Tighten the nuts (2) to 9 N·m (80 lb in).

10. Install the rear compartment trim. Refer to Rear Compartment Trim Panel Replacement .
11. Reconfigure the OnStar® system. Refer to OnStar Reconfiguration .

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