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Seat Belt Indicator Circuit Malfunction - Passenger

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit

Short to Ground

High Resistance

Open

Short to Voltage

Signal Performance

Passenger Seat Belt Switch Signal

1

2

2

2

-

Passenger Seat Belt Switch Low Reference

-

2

2

2

-

1. Indicator will remain ON with seat belt buckled.

2. Indicator will illuminate only for the bulb check.

Circuit/System Description

When an individual is sitting in the passenger seat the passenger presence sensor detects the individual. A signal to the SDM indicates a person is in the passenger seat. The SDM will turn the passenger seat belt indicator on while someone is seating in the passenger seat. The passenger 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 passenger seat belt via a hard wire to the passenger air bag disable indicator. The passenger air bag disable indicator will then control the illumination of the passenger seat belt indicator.

Reference Information

Schematic Reference

Seat Belt Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Seat Belt System Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Vehicle in Service Mode.
  2. With a scan tool, Command the Passenger Seat Belt Reminder Indicator ON and OFF.
  3. If the passenger seat belt reminder indicator turns ON and OFF as commanded, refer to Passenger Seat Belt Switch Malfunction.
    If the passenger seat belt reminder indicator does not turn ON and OFF as commanded, refer to Passenger Seat Belt Indicator Malfunction.

Circuit/System Testing

Passenger Seat Belt Switch Malfunction

  1. Vehicle OFF.
  2. Disconnect the harness connector at the appropriate B88 passenger seat belt switch.
  3. Test for less than 5 Ω between the low reference circuit terminal 2 and ground.
  4. If 5 Ω or greater
    3.1. Disconnect the harness connector at the K36 SDM.
    3.2. Test for less than 2 Ω in each control circuit end to end.
    ⇒     If 2 Ω or greater, repair the open/high resistance in the circuit.
    ⇒     If less than 2 Ω, replace the K36 SDM.
    ⇓     If less than 5 Ω
  5. Vehicle in Service Mode.
  6. Verify the scan tool Passenger Seat Belt Status parameter listed below is Buckled.
  7. If the scan tool Passenger Seat Belt Status parameter does not display Buckled
    5.1. Disconnect the harness connector at the K36 SDM.
    5.2. Test for infinite resistance between the seat belt switch signal circuit terminal 1 and ground.
    ⇒     If less than infinite resistance, repair the short to ground on the circuit.
    ⇒     If less than 2 Ω, replace the K36 SDM.
    ⇓   If the scan tool Passenger Seat Belt Status parameter does display Buckled
  8. Install a 3 A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2.
  9. Verify the scan tool Passenger Seat Belt Status parameter is Unbuckled.
  10. If the scan tool Passenger Seat Belt Status parameter does not display Unbuckled
    7.1. Disconnect the harness connector at the K36 SDM.
    7.2. Vehicle in Service Mode.
    7.3. Test for less than 1 V between the signal circuit and ground.
    ⇒     If 1 V or greater, repair the short to voltage on the circuit.
    7.4. Test for less than 2 Ω in each circuit end to end.
    ⇒     If 2 Ω or greater, repair the open/high resistance in the circuit.
    ⇒     If less than 2 Ω, replace the K36 SDM.
    ⇓   If the scan tool Passenger Seat Belt Status parameter does display Unbuckled
  11. Replace the B88 passenger seat belt switch.

Passenger Seat Belt Indicator Malfunction

  1. Vehicle OFF.
  2. Disconnect the harness connector at the P14 passenger air bag disable indicator.
  3. Test for less than 10 Ω between the ground circuit terminal 2 and ground.
  4. If 10 Ω or greater
        Repair the open/high resistance in the circuit.
    ⇓   If less than 10 Ω
  5. Vehicle in Service Mode.
  6. With a scan tool, command the Passenger Seat Belt Reminder Indicator OFF.
  7. Test for less than 11 V between the control circuit terminal 5 and ground.
  8. If 11 V or greater
    6.1. Vehicle OFF.
    6.2. Disconnect the X1 harness connector at the K36 SDM.
    6.3. Vehicle in Service Mode.
    6.4. Test for less than 1 V between the control circuit and ground.
    If 1 V or greater, repair the short to voltage on the circuit.
    If less than 1 V, replace the K36 SDM.
    ⇓   If less than 11 V
  9. With a scan tool, command the Passenger Seat Belt Reminder Indicator ON.
  10. Test for greater than 4 V between the control circuit terminal 5 and ground.
  11. If 4 V or less
    8.1. Vehicle OFF.
    8.2. Disconnect the X 1 harness connector at the K36 SDM.
    8.3. Test for infinite resistance between the control circuit and ground.
    If less than infinite resistance, repair the short to ground on the circuit.
    8.4. Test for less than 2 Ω between the control circuit and ground.
    If 2 Ω or greater repair the open/high resistance in the circuit.
    If less than 2 Ω replace the K36 SDM.
    ⇓   If greater than 4 V
  12. Replace the P14 passenger air bag disable indicator.

Component Testing

  1. Vehicle OFF.
  2. Disconnect the harness connector at the appropriate B88 seat belt switch.
  3. Buckle the B88 seat belt switch.
  4. Test for infinite resistance between the signal circuit terminal 1 and the low reference terminal 2 at the B88 seat belt switch.
  5. If there is not infinite resistance
        Replace the B88 seat belt switch.
    ⇓   If there is infinite resistance
  6. Unbuckle the B88 seat belt switch.
  7. Test for less than 1 Ω between the signal circuit terminal 1 and the low reference terminal 2 at the B88 seat belt switch.
  8. If 1 Ω or greater
        Replace the B88 seat belt switch.
    ⇓   If less than 1 Ω
  9. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Front Seat Belt Buckle Replacement
    •  Inflatable Restraint Instrument Panel Module Indicator Replacement
    • Control Module References for SDM and Passenger Presence System replacement, programming and setup
   


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