Seat Belt Indicator Circuit Malfunction (with WHB)
Seat Belt Indicator Circuit Malfunction (with WHB)
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 driver seat belt switch is a 2-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. The SDM sends the status of the driver seat belt via serial data to the instrument panel cluster (IPC). After receiving the message, the IPC controls the illumination of the driver seat belt indicator.
Reference Information
Schematic Reference
Seat Belt Schematics ([1][2]Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
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, with a scan tool perform the IPC Display Test and verify the driver seat belt indicator is illuminated for 5 seconds.
• If the indicator does not illuminate, replace the IPC.
2. Monitor the scan tool Driver Seat Belt Switch parameter while connecting and disconnecting the seat belt. The parameter should display Buckled and Not Buckled when changing seat belt states.
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.
* Seat belt switch
* Seat belt switch harness connector
* SDM
* SDM wiring harness connector
1. Ignition OFF, disconnect the harness connector at the seat belt switch.
2. Ignition OFF, test for less than 1 ohm between the ground circuit terminal 2 and ground.
• If greater than the specified range, test the low reference circuit for a short to voltage or an open/high resistance.
3. Ignition ON, verify the scan tool Driver Seat Belt Switch parameter displays Buckled.
• If not the specified value, test the signal circuit for a short to ground. If the circuit tests normal replace the SDM.
4. Install a 3A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2. Verify the scan tool Driver Seat Belt Switch parameter displays Not 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, test or replace the seat belt switch.
Component Testing
1. Ignition OFF, disconnect the harness connector at the seat belt switch.
2. With the seat belt buckled, test for infinite resistance between the signal circuit terminal 1 and the low reference terminal 2.
• If less than the specified value, replace the seat belt switch.
3. With the seat belt unbuckled, test for less than 1 ohm between the signal circuit terminal 1 and the low reference terminal 2.
• If greater than the specified range, replace the seat belt switch.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Driver or Passenger Belt Replacement (Driver or Passenger Belt Replacement)
* Control Module References (Programming and Relearning) for SDM and IPC replacement, setup, and programming