The seat belt buckle switch is a two wire switch wired to the inflatable restraint sensing and diagnostic module (SDM) using a signal circuit and a low reference circuit. When the seat belt is unbuckled the switch is closed, and when the seat belt is buckled the switch is open. When the passenger presence system (PPS) indicates that the seat is occupied, the SDM sends the status of the passenger seat belt via serial data to the instrument panel cluster (IPC). After receiving the message, the IPC controls the illumination of the passenger seat belt indicator by grounding the indicator control circuit. If an occupant is seated in the front passenger seat and the seat belt is unfastened, the SDM will send a message to the IPC to illuminate the fasten seat belt indicator for approximately 72 seconds or until the seat belt is fastened.

Schematic Reference

Connector End View Reference

Electrical Information Reference

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 module

•	The seat belt switch - right

•	The SDM module

•	The seat belt switch - right wiring harness connector

•	The SDM wiring harness connector

1. Observe the Passenger Air Bag ON/OFF status indicator. Turn ON the ignition, both ON and OFF indicators should turn ON for 5 seconds.

⇒	If the Passenger Air Bag ON/OFF status indicators do not illuminate, refer to Passenger Presence System Indicator Circuit Malfunction .

2. Using the scan tool, perform the display test special function in instrument panel cluster. The passenger seat belt indicator should illuminate.

⇒	If the indicator does not illuminate, test the control and ground circuits of the indicator for high resistance/open, short to ground, or short to voltage. If the circuits test normal, replace the instrument panel inflatable restraint module indicator.

3. Ignition OFF, disconnect the seat belt switch connector.
4. Test the resistance between the low reference circuit terminal B and signal circuit terminal A of the switch (buckle side) while connecting and disconnecting the seat belt. The resistance should switch between infinity and less than 2 ohms.

⇒	If the resistance is not as specified, replace the seat belt buckle.

5. Ignition OFF, remove the SDM connector, refer to module replacement. Test the seat belt switch signal and low reference circuits for high resistance/open, short to ground, or short to voltage.

⇒	If any of the above conditions are found, make the appropriate repair.

6. If the circuits test normal, replace the SDM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.