Seat Belt Indicator Circuit Malfunction - Driver

Seat Belt Indicator Circuit Malfunction - Driver

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.

Diagnostic Fault Information





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)
* SIR Schematics ([1][2]Air Bag Systems)

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 SDM Driver Seat Belt Switch parameter while connecting and disconnecting the seat belt. The parameter should display Buckled and Unbuckled 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 appropriate component/connector:


* The SDM

* The SDM wiring harness connector

* The seat belt buckle

* The seat belt buckle wiring harness connector


1. Ignition OFF, disconnect the harness connector at the driver seat belt switch.
2. Ignition OFF, test for less than 10 ohms between the low reference circuit terminal B 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, verify the scan tool Driver Seat Belt Switch parameter is Unbuckled.

• If not the specified value, test the signal circuit terminal A 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 A and the low reference circuit terminal B. 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, test or replace the seat belt buckle assembly.

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 A and the low reference terminal B.

• If not the specified range, replace the seat belt switch.

3. With the seat belt unbuckled, test for less than 2 ohms of resistance between the signal circuit terminal A and the low reference terminal B.

• 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 Seat Belt Buckle Replacement (Driver or Passenger Seat Belt Buckle Replacement)
* Control Module References (Programming and Relearning)for SDM and IPC replacement, setup, and programming