Seat Belt Indicator Circuit Malfunction - Passenger

Seat Belt Indicator Circuit Malfunction - Passenger

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions)provides an overview of each diagnostic category.

Circuit/System Description

The inflatable restraint sensing and diagnostic module (SDM) sends the status of the passenger seat belt switch to the body control module (BCM) via a serial data communication message. If the seat belt of an occupied seat is unfastened, the SDM will send a message to the BCM to illuminate the fasten safety belt indicator for 72 seconds or until the seat belt is fastened.

Reference Information
Schematic Reference

Seat Belt Schematics ([1][2]Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector End Views By Name)
Description and Operation

Seat Belt System Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning)for scan tool information

Circuit/System Verification

1. Ignition ON, observe the function of the passenger seat belt indicator while commanding the BCM to turn the passenger seat belt indicator lamp ON and OFF with a scan tool. The seat belt indicator should turn ON and OFF when changing between the commanded states.

• If the seat belt indicator does not follow the commanded states, refer to BCM Seat Belt Indicator Malfunction.

2. Ignition ON, with the passenger seat occupied, buckle and unbuckle the passenger seat belt, the seat belt indicator should go ON and OFF while buckling and unbuckling the occupied seat.

• If the seat belt indicator lamp is not working properly, refer to SDM Seat Belt Indicator Malfunction.
• If the seat belt indicator lamp is always OFF, refer to Seat Belt Indicator Always OFF.

Circuit/System Testing

BCM Seat Belt Indicator Malfunction
1. Ignition ON, have someone sit in the passenger seat with the passenger seat belt unbuckled. and verify the SDM scan tool Passenger Seat Belt Switch parameter is Buckled. Connect a test lamp between the passenger air bag on/off indicator terminal 5 and ground. The test light should illuminate.

• If not test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

2. Connect the test light between the passenger air bag on/off indicator control circuit terminal 5and the low reference terminal 2. The test light should illuminate.

• If not repair the low reference circuit for a short to voltage or an open/high resistance.

3. If all circuits test normal, test or replace the passenger air bag on/off indicator.

SDM Seat Belt Indicator Malfunction
1. Ignition OFF, disconnect the harness connector at the passenger seat belt buckle.
2. Connect a fused jumper wire between the seat belt switch signal circuit terminal A and ground.
3. Ignition ON, 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 an open/high resistance. If the circuit tests normal, replace the SDM.

4. Connect a fused jumper wire between the seat belt switch signal circuit terminal A and the low reference terminal C.
5. Verify the scan tool Passenger Seat Belt Switch parameter is Buckled.

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

6. If all circuits test normal, test or replace the passenger seat belt buckle.

Component Testing

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

• If not the specified value, replace the passenger seat belt buckle.

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

• If greater than the specified range, replace the passenger seat belt buckle.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Front Seat Belt Buckle Replacement (Front Seat Belt Buckle Replacement)
* Inflatable Restraint Instrument Panel Module Indicator Replacement (Service and Repair)
* Control Module References (Programming and Relearning)for SDM or BCM replacement, setup, and programming