The inflatable restraint sensing and diagnostic module (SDM) communicates the status of the passenger seat belt switch to the body control module (BCM). When the ignition switch is turned ON with the driver seat belt buckled and an occupant detected in the passenger seat, the BCM illuminates the passenger fasten safety belt indicator for 72 seconds or until the seat belt is fastened. If the passenger seat belt is buckled before the driver seat belt is buckled, the passenger fasten safety belt indicator will remain OFF. When the seat belt is unbuckled, the seat belt switch is Closed. When the seat belt is buckled, the seat belt switch is Open.

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

Ignition ON, with the driver seat belt buckled and an occupant in the passenger seat, buckle and unbuckle the passenger seat belt. The passenger seat belt indicator should go ON and OFF while buckling and unbuckling the passenger seat belt.

1. Ignition OFF, disconnect the harness connector at the driver seat belt buckle.
2. Ignition OFF, test for less than 5 ohms between the seat belt switch low reference circuit terminal A 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, test for 4.8-5.2 volts between the seat belt 5-volt signal circuit terminal B and ground.

⇒	If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the SDM.

⇒	If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the SDM.

4. Ignition ON, with a scan tool command the passenger seat belt indicator ON and OFF. The passenger seat belt indicator should turn ON and OFF when changing between the commanded states.

⇒	If the seat belt indicator operates normally, test or replace the seat belt switch.

5. Ignition OFF, disconnect the harness connector at the inflatable restraint instrument panel module indicator.
6. Ignition ON, test for B+ between the passenger seat belt indicator ignition voltage circuit terminal 4 and ground.

⇒	If less than the specified range, test the ignition voltage circuit for an open/high resistance.

7. Ignition ON, with the passenger seat occupied buckle both the driver and the passenger seat belts. Verify that a test lamp does not illuminates between the passenger seat belt indicator control circuit terminal 5 and B+.

⇒	If the test lamp illuminated, test the indicator control circuit for a short to ground. If the circuit tests normal, replace the BCM

8. With the passenger seat still occupied, unbuckle the passenger seat belt. Verify that a test lamp illuminates between the passenger seat belt indicator control circuit terminal 5 and B+.

⇒	If the test lamp does not illuminate, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.

9. If all circuits test normal, test or replace the inflatable restraint instrument panel module indicator.

Seat Belt Switch

1. Ignition OFF, disconnect the harness connector at the driver seat belt buckle.
2. Test for infinite resistance between the signal terminal B and the low reference terminal A with the seat belt buckle buckled.

⇒	If not the specified value, replace the driver seat belt buckle.

3. Test for less than 2.0 ohms between the signal terminal B and the low reference terminal A with the seat belt buckle unbuckled.

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

Passenger Seat Belt Indicator

1. Ignition OFF, disconnect the harness connector at the inflatable restraint instrument panel module indicator.
2. Install a 2A fused jumper wire between the ignition voltage circuit terminal 4 and B+. Momentarily install a jumper wire between the indicator control circuit terminal 5 and ground. Verify the passenger seat belt indicator illuminates.

⇒	If the indicator does not illuminate, replace the inflatable restraint instrument panel module indicator.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.