GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

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

Circuit/System Description

The Passeneger Presence System sensor detects if the seat is occupied and the passenger seat belt switch detects seat belt status, the signals are sent to the IPC via a serial data communication message. The instrument panel cluster (IPC) controls the passenger seat belt indicator by using the serial data communication message.

Reference Information

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

    •  Circuit Testing
    •  Testing for Intermittent Conditions and Poor Connections
    •  Connector Repairs
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

    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 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 located in the instrument panel (I/P). Turn ON the ignition, both ON and OFF indicators will turn ON for 5 seconds. Verify that the Passenger Air Bag ON/OFF status indicator illuminates.
  2. If the Passenger Air Bag ON/OFF status indicator does not illuminate, refer to Passenger Presence System Indicator Circuit Malfunction .
  3. Sit in the front passenger seat with the ignition ON and observe the Passenger Air Bag ON/OFF indicator, which contains the passenger seat belt indicator. Monitor the passenger seat belt indicator while buckling and unbuckling the passenger seat belt. The passenger seat belt indicator should turn OFF and ON when the passenger seat belt is unbuckled and buckled. Verify that the passenger seat belt indicator turns ON and OFF.
  4. If the indicator does perform as described, test and repair both seat belt switch - right signal and ground circuit for an open, high resistance. If both circuits test normal then replace the seat belt switch - right.
  5. Ignition OFF, remove the IPC connector and the Passenger Air Bag ON/OFF connector. Refer to Inflatable Restraint Instrument Panel Module Replacement .
  6. Test the Passenger Seat Belt Indicator Control circuit between the IPC and the passenger Air Bag ON/OFF connector for an open or high resistance. Verify that an open or high resistance does not exist.
    If any of the above conditions are found, make the appropriate repair.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Front Seat Belt Buckle Replacement
    •  Inflatable Restraint Instrument Panel Module Replacement
    •  Control Module References for SDM and BCM replacement, setup, and programming