For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### Circuit/System Description

The inflatable restraint sensing and diagnostic module (SDM) sends the status of the driver seat belt switch to the instrument panel cluster (IPC) via a serial data communication message. If the seat belt is unfastened, the SDM will send a message to the IPC to illuminate the fasten safety belt indicator for 72 seconds or until the seat belt is fastened.

### Reference Information

#### Schematic Reference

Seat Belt Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Seat Belt System Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Testing for Intermittent Conditions and Poor Connections

• | Connector Repairs

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Testing

Important: When removing connectors inspect for damage or corrosion. Damage or corrosion in the following requires repair or replacement of the affected component/connector.

• | The seat belt switch - left

• | The SDM module

• | The seat belt switch - left wiring harness connector

• | The SDM wiring harness connector

1. Observe the fasten seat belt indicator located in the IPC. Turn ON the ignition and use the scan tool. Buckle the driver seat belt and monitor the Driver Side Belt Status parameter in the SIR scan tool data list in the scan tool. Verify that the Seat Belt indicator turns ON while the scan tool shows the driver seat belt is buckled.

⇒ | If the scan tool displays the driver seat belt is buckled and the driver seat belt indicator does not turn ON, replace the IPC.

2. Sit in the front driver seat with the ignition ON and with a scan tool. Monitor the scan tool and while buckling and unbuckling the driver seat belt, verify the scan tool is showing the driver seat belt is buckling and unbuckling.

⇒ | If the scan tool indicates that the driver seat belt does perform as described, turn OFF the ignition, remove the SDM connector and the driver seat belt buckle connector. Test and repair both seat belt switch - left signal and ground circuit for an open, high resistance or replace the seat belt switch - left.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Front Seat Belt Buckle Replacement

• | Control Module References for SDM and IPC replacement, setup, and programming