For 1990-2009 cars

### Removal Procedure

Warning: Refer to Battery Disconnect Warning in the Preface section.

1. Disconnect the battery ground cable.
2. Slide the passenger seat rearward.
3. Disconnect the electrical connector from the Onstar module which is located on the bottom of the passenger seat.
4. Remove the bolts (1) and the Onstar battery (2).

### Installation Procedure

Caution: Refer to Fastener Caution in the Preface section.

1. Install the Onstar battery (2) with the bolts (1) and tighten to 3 N·m (27 lb in).
2. Restore the seat position.
3. Connect the electrical connectors.
4. Connect the negative battery cable.