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 cluster. After receiving the message, the instrument cluster 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 End Views By Name)
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. Command the instrument cluster all indicators ON and OFF with a scan tool. The driver seat belt indicator should turn ON and OFF as commanded.
• If the driver seat belt indicator does not turn ON and OFF as expected, replace the P16 instrument cluster.
2. Monitor the scan tool Driver Seat Belt Switch parameter while buckling and unbuckling the seat belt. The parameter should display Buckled and Unbuckled when changing seat belt states.
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.
* Seat belt switch
* Seat belt switch harness connector
* SDM
* SDM wiring harness connector
1. Ignition OFF, disconnect the harness connector at the B88 seat belt switch.
2. Ignition OFF, test for less than 1 ohm between the low reference circuit terminal 1 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 K36 SDM.
3. Ignition ON, verify the scan tool Driver Seat Belt Status parameter displays Buckled.
• If not the specified value, test the signal circuit for a short to ground. If the circuit tests normal replace the K36 SDM.
4. Install a 3 A fused jumper wire between signal circuit terminal 2 and low reference circuit terminal 1. Verify the scan tool Driver Seat Belt Status parameter displays Unbuckled.
• 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 K36 SDM.
5. If all circuits test normal, test or replace the appropriate B88 seat belt switch or P16 instrument cluster.
Component Testing
1. Ignition OFF, disconnect the harness connector at the B88 seat belt switch.
2. With the seat belt buckled, test for infinite resistance between the signal circuit terminal 2 and the low reference terminal 1.
• If less than the specified value, replace the B88 seat belt switch.
3. With the seat belt unbuckled, test for less than 1 ohm between the signal circuit terminal 2 and the low reference terminal 1.
• If greater than the specified range, replace the B88 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 instrument cluster replacement, setup, and programming