Seat Belt Indicator Circuit Malfunction - Driver

Seat Belt Indicator Circuit Malfunction - Driver

Diagnostic Fault Information
Perform the [Diagnostic System Check - Vehicle Diagnostic Information] prior to using this diagnostic procedure.

Circuit/System Description
The inflatable restraint sensing and diagnostic module (SDM) sends the status of the driver seat belt switch to the instrument panel cluster (IPC) via a GMLAN serial data message. If the seat belt is unfastened, the SDM will send a message to the IPC to illuminate the fasten safety belt indicator for 72 seconds or until the seat belt is fastened.

Reference Information

Schematic Reference
^ [Seat Belt Schematics
^ [SIR Schematics]

Connector End View Reference
[Seat Belt Connector End Views]

Description and Operation
[Seat Belt System

Description and Operation] Electrical Information Reference
^ [Circuit Testing]
^ [Connector Repairs]
^ [Testing for Intermittent Conditions and Poor Connections]
^ [Wiring Repairs]

Scan Tool Reference
^ [Scan Tool Data List - SIR]
^ [Scan Tool Data Definitions - SIR]

Circuit/System Verification
Ignition ON, perform the IPC Display Test using the scan tool and verify the driver seat belt indicator is illuminated.
^ If the indicator does not illuminate, replace the IPC.

Circuit/System Testing

NOTE: 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
^ The left seat belt switch
^ The SDM
^ The left seat belt switch harness connector
^ The SDM wiring harness connector

1. Ignition OFF, disconnect the harness connector at the left seat belt switch.
2. Ignition OFF, test for less than 1.0 ohms of resistance between the low reference circuit terminal A and ground.
^ If greater than the specified value, 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 driver seat belt switch parameter is Unbuckled.
^ If not the specified value, test the signal circuit terminal 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 B and the low reference circuit terminal A. Verify the scan tool driver 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.

5. If all circuits test normal, replace the left seat belt switch.

Component Testing
1. Ignition OFF, disconnect the harness connector at the left seat belt switch.
2. Test for infinite resistance between the signal circuit terminal B and the low reference terminal A.
^ If not the specified value, replace the left seat belt switch.

3. With the seat belt buckled, test for less than 2 ohms of resistance between the signal circuit terminal B and the low reference terminal A.
^ If greater than the specified range, replace the left seat belt switch.

Repair Instructions
Perform the [Diagnostic Repair Verification - Vehicle Diagnostic Information] after completing the diagnostic procedure.
^ [Front Seat Belt Buckle Replacement]
^ [Control Module References] for SDM and IPC replacement, setup, and programming Programming and Relearning