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.

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

Scan Tool Reference

Control Module References for scan tool information.

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 buckle.

⇒	If the scan tool displays the driver seat belt is buckled and 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. Refer to SDM replacement in Repair Instructions for connector location.

⇒	Test and repair both seat belt switch - left signal and ground circuits for an open, high resistance.

3. If all circuits test normal then replace the seat belt pretensioner - left.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.