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 GMLAN serial data 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

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

Ignition ON, perform the IPC Display Test using the scan tool and verify the driver seat belt indicator is illuminated.

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 BCM

•	The left seat belt switch

•

The SDM

•	The left seat belt switch harness connector

•	The SDM wiring harness connector

1. Ignition OFF, disconnect the harness connector at the left seat belt switch.
2. Ignition OFF, test for less than 1.0 ohm of resistance between the low reference circuit terminal C and ground.

⇒	If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the SDM.

3. Ignition ON, verify the scan tool driver seat belt switch parameter is Unbuckled.

⇒	If not the specified value, test the signal circuit for a short to ground. If the circuit tests normal replace the SDM.

4. Install a 3-amp fused jumper wire between the signal circuit terminal A and the low reference circuit terminal C. Verify the scan tool driver seat belt switch parameter is Buckled.

⇒	If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the SDM.

5. If all circuits test normal, replace the left seat belt switch.

1. Ignition OFF, disconnect the harness connector at the left seat belt switch.
2. Test for infinite resistance between the signal circuit terminal A and the low reference terminal C.

⇒	If not the specified value, replace the left seat belt switch.

3. With the seat belt buckled, test for less than 2 ohms of resistance between the signal circuit terminal A and the low reference terminal C.

⇒	If greater than the specified range, replace the left seat belt switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.