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

The inflatable restraint sensing and diagnostic module (SDM) sends the status of the seat belt switch - right to the instrument panel cluster (IPC) via a GMLAN serial data message. The IPC controls power to the passenger seat belt indicator to turn the indicator on/off. The SDM will only send a command to the IPC to turn the indicator on when the seat belt is unbuckled and the SDM senses an occupant in the passenger seat.

Schematic Reference

Connector End View Reference

Description and Operation

Seat Belt System Description and Operation

Electrical Information Reference

Scan Tool Reference

Ignition ON, while sitting in the passenger seat, observe the passenger seat belt indicator. Buckle and unbuckle the passenger seat belt, the indicator should turn off when buckled and turn on when unbuckled.

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

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

⇒	If greater than the specified range, 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 passenger seat belt switch parameter is Unbuckled.

⇒	If not the specified value, test the signal circuit terminal A 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 B. Verify the scan tool Passenger Seat Belt Switch parameter is Buckled.

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

5. Ignition OFF, reconnect the harness connector at the seat belt switch - right.
6. Ignition ON, while sitting in the passenger seat, observe the scan tool Passenger Seat Belt Switch parameter. Buckle and unbuckle the passenger seat belt; the parameter should change between buckled and unbuckled.

⇒	If the parameter does not change, test or replace the seat belt switch - right.

7. Ignition OFF, disconnect the harness connector at the inflatable restraint I/P module indicator.
8. Ignition ON, verify a test lamp illuminates between the ignition circuit terminal 4 and ground.

⇒	If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.

9. Connect a test lamp between the ignition circuit terminal 4 and the control circuit terminal 5.
10. While sitting in the passenger seat, observe the scan tool Passenger Seat Belt Switch parameter. Buckle and unbuckle the passenger seat belt; the parameter should change between buckled and unbuckled.

⇒	If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the IPC.

⇒	If the test lamp is always OFF, test the control circuit for a short to voltage or and open/high resistance. If the circuit tests normal, replace the IPC.

11. If all circuits test normal, test or replace the Inflatable Restraint I/P Module Indicator.

Inflatable Restraint I/P Module Indicator

1. Install a 10A fused jumper wire between the ignition circuit terminal 4 and 12 volts. Install a jumper wire between the control circuit terminal 5 and ground.
2. Verify the passenger seat belt indicator illuminates.

⇒	If the function does not perform as specified, replace the Inflatable Restraint I/P Module Indicator.

Seat Belt Switch

1. Ignition OFF, disconnect the harness connector for the seat belt switch.
2. Test for infinite resistance between the signal terminal A and the low reference circuit terminal B with the switch in the open position.

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

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

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.