Seat Belt Indicator Circuit Malfunction - Passenger

Seat Belt Indicator Circuit Malfunction - Passenger

Diagnostic Instructions

* Perform theDiagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* ReviewStrategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.



Diagnostic Fault Information






Circuit/System Description

The seat belt buckle switch is located within the seat belt buckle assembly and provides an input to the inflatable restraint sensing and diagnostic module (SDM). The SDM supplies a low reference circuit and a seat belt switch signal circuit to determine a buckled or unbuckled condition.


If the SDM determines the driver seat belt has not been buckled, the SDM will send a serial data message to the instrument panel cluster (IPC) to illuminate the seat belt warning indicator. If the SDM determines that a passenger is sitting in the passenger seat and the seat belt has not been buckled, the SDM will send a serial data message to the passenger presence system (PPS) display to illuminate the passenger seat belt warning indicator.


Reference Information
Schematic Reference

* Seat Belt Schematics ([1][2]Electrical Diagrams)
* SIR Schematics ([1][2]Air Bag Systems)
* Seat Belt Schematics ([1][2]Electrical Diagrams)

Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

SIR System Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

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


Circuit/System Verification

1. Ignition ON, observe the scan tool Passenger Seat Belt Switch parameter while buckling and unbuckling the passenger seat belt. The parameter should change between Buckled and Unbuckled.

• If the parameter does not cycle between the specified values, refer to Passenger Seat Belt Switch Circuit Malfunction.

2. Ignition ON, while sitting in the passenger seat with the seat belt unbuckled, verify the passenger seat belt warning indicator is illuminated on the PPS display.

• If the indicator is not illuminated, replace the PPS display.




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





Passenger Seat Belt Switch Circuit Malfunction
1. Ignition OFF, disconnect the harness connector at the passenger seat belt switch.
2. Ignition OFF, test for less than 10 ohms between the low reference circuit terminal B X1 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 Passenger Seat Belt Switch parameter is Unbuckled.

• If not the specified value, test the signal circuit terminal A X1 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 X1 and the low reference circuit terminal B X1. 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.

5. If all circuits test normal, test or replace the seat belt buckle assembly.



Repair Instructions

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

* Seat Belt Retractor Pretensioner Replacement - Front (Regular Cab) (Seat Belt Retractor Pretensioner Replacement - Front (Regular Cab))Seat Belt Retractor Pretensioner Replacement - Front (Extended Cab) (Seat Belt Retractor Pretensioner Replacement - Front (Extended Cab))Seat Belt Retractor Pretensioner Replacement - Front (Crew Cab) (Seat Belt Retractor Pretensioner Replacement - Front (Crew Cab))
* Control Module References (Programming and Relearning) for SDM replacement, setup, and programming