Seat Belt Indicator Circuit Malfunction

Seat Belt Indicator Circuit Malfunction

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 inflatable restraint sensing and diagnostic module (SDM) sends the status of the driver and passenger seat belt switch to the instrument panel cluster (IPC) via a serial data communication message. If the seat belt of an occupied seat 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 (Seat Belt Schematics)
Connector End View Reference

Component Connector End Views (Component Connector End 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 (Control Module References) for scan tool information

Circuit/System Verification

1. Ignition ON, observe the function of the seat belt indicator lamp while commanding the I/P lamps ON and OFF with a scan tool. The seat belt indicator lamp should turn ON and OFF when changing between the commanded states.

• If the seat belt indicator is always OFF, replace the I/P cluster

2. Ignition ON, with the appropriate seat occupied, buckle and unbuckle the appropriate seat belt, the seat belt indicator should go ON and OFF while buckling and unbuckling the occupied seat.

• If the seat belt indicator lamp is always ON, refer to Seat Belt Indicator Always ON.
• If the seat belt indicator lamp is always OFF, refer to Seat Belt Indicator Always OFF.

Circuit/System Testing

Seat Belt Indicator Always ON
1. Ignition OFF, disconnect the harness connector at the appropriate seat belt buckle.
2. Ignition ON, verify the scan tool Seat Belt Switch parameter is Unbuckled.

• If not the specified value, test the signal circuit terminal B for a short to ground. If the circuit tests normal, replace the SDM.

3. If all circuits test normal, test or replace the appropriate seat belt buckle.

Seat Belt Indicator Always OFF
1. Ignition OFF, disconnect the harness connector at the appropriate seat belt buckle.
2. Connect a fused jumper wire between the seat belt switch signal circuit terminal B and the seat position sensor return circuit terminal A.
3. Ignition ON, verify the scan tool Seat Belt Switch parameter is Buckled.

• If not the specified value, test either circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the SDM.

4. If all circuits test normal, test or replace the appropriate seat belt buckle.

Component Testing

1. Ignition OFF, disconnect the harness connector at the appropriate seat belt buckle.
2. Test for infinite resistance between the signal terminal B and the return circuit terminal A with the seat belt buckle unbuckled.

• If not the specified value, appropriate seat belt buckle.

3. Test for less than 2.0 ohms between the signal terminal B and the return circuit terminal A with the seat belt buckle buckled.

• If greater than the specified range, replace the appropriate seat belt buckle.

Repair Instructions

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

* SIR/SRS Wiring Repairs (SIR/SRS Wiring Repairs)
* Front Seat Belt Buckle Replacement (Front Seat Belt Buckle Replacement)
* Control Module References (Control Module References) for SDM and IPC replacement, setup, and programming