Seat Belt Indicator Circuit Malfunction - Passenger
Seat Belt Indicator Circuit Malfunction - Passenger
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
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 [1][2]Electrical Diagrams
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 Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Have someone sit in the passenger seat.
3. With a scan tool verify the Automatic Occupant Sensing Current Front Occupancy Status indicates Occupied.
• If the Automatic Occupant Sensing Current Front Occupancy Status does not indicate Occupied
1. Disconnect the harness connector at the K36 SDM.
2. Test for infinite resistance between the following circuits terminal and ground:
- Sensor signal circuit terminal
- Sensor low reference circuit terminal
• If less than infinite resistance, repair the short to ground on the circuit.
3. Test for less than 2 ohm in each circuit end to end.
• If 2 ohm or greater, repair the open/high resistance in the circuit.
• If less than 2 ohm, replace the passenger presence sensor.
• If the Automatic Occupant Sensing Current Front Occupancy Status does indicate Occupied
4. Ignition ON.
5. With a scan tool perform the Passenger Seat Belt Reminder Indicator On/Off Control Function and verify the passenger seat belt indicator turns on and off.
• If the passenger seat belt indicator does not turn on and off
• Replace the inflatable restraint instrument panel module indicator.
• If the passenger seat belt indicator does turn on and off
• Replace the inflatable restraint instrument panel module indicator.
6. With the scan tool monitor the Passenger Seat Belt Status parameter while buckling and unbuckling the seat belt. The parameter should display Buckled and Unbuckled when buckling and unbuckling the seat belt.
• If the Passenger Seat Belt Status parameter does not display Buckled and Unbuckled
• Refer to Circuit/System Testing below.
• If the Passenger Seat Belt Status parameter does display Buckled and Unbuckled
7. Monitor the scan tool Passenger Seat Belt Switch parameter while connecting and disconnecting the seat belt switch connector. The parameter should display Buckled and Unbuckled when changing seat belt states. If the status does not change states refer to Circuit/System Testing below.
• If the Passenger Seat Belt Status parameter does not display Buckled and Unbuckled
• Refer to Circuit/System Testing below.
• If the Passenger Seat Belt Status parameter does display Buckled and Unbuckled
8. All OK.
Circuit/System Testing
Seat Belt Switch Malfunction
1. Ignition OFF.
2. Disconnect the harness connector at the appropriate B88 passenger seat belt switch.
3. Test for less than 5 ohm between the ground circuit terminal B and ground.
• If 5 ohm or greater
1. Disconnect the harness connector at the K36 SDM.
2. Test for less than 2 ohm in each control circuit end to end.
• If 2 ohm or greater, repair the open/high resistance in the circuit.
• If less than 2 ohm, replace the K36 SDM.
• If less than 5 ohm
4. Ignition ON.
5. Verify the scan tool Passenger Seat Belt Status parameter listed below is Buckled.
• If the scan tool Passenger Seat Belt Status parameter does not display Buckled
1. Disconnect the harness connector at the K36 SDM.
2. Test for infinite resistance between the seat belt switch signal circuit terminal 2 and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If less than 2 ohm, replace the K36 SDM.
• If the scan tool Passenger Seat Belt Status parameter does display Buckled
6. Install a 3 A fused jumper wire between the signal circuit terminal A and the ground circuit terminal B.
7. Verify the scan tool Passenger Seat Belt Status parameter is Unbuckled.
• If the scan tool Passenger Seat Belt Status parameter does not display Unbuckled
1. Disconnect the harness connector at the K36 SDM.
2. Ignition ON.
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.
4. Test for less than 2 ohm in each circuit end to end.
• If 2 ohm or greater, repair the open/high resistance in the circuit.
• If less than 2 ohm, replace the K36 SDM.
• If the scan tool Passenger Seat Belt Status parameter does display Unbuckled
8. Replace the B88 passenger seat belt switch.
Seat Belt Indicator Malfunction
1. Ignition OFF.
2. Disconnect the harness connector at the P14 passenger air bag disable indicator.
3. Test for less than 5 ohm between the ground circuit terminal 2 and ground.
• If 5 ohm or greater
1. Disconnect the harness connector at the K36 SDM.
2. Test for less than 2 ohm in each control circuit end to end.
• If 2 ohm or greater, repair the open/high resistance in the circuit.
• If less than 2 ohm, replace the K36 SDM.
• If less than 5 ohm
4. Connect a test lamp between the control circuit terminal 5 and ground.
5. Ignition ON.
6. Command the Passenger Seat Belt Reminder ON and OFF with a scan tool, the test lamp should turn ON and OFF while changing between the commanded states.
• If the test lamp is always on
1. Ignition OFF.
2. Disconnect the harness connector at the K36 SDM.
3. Ignition ON.
4. Test for less than 1 V between the signal circuit and ground.
• If 1V or greater, repair the short to voltage on the circuit.
• If less than 1V, replace the K36 SDM.
• If the test lamp is always off
1. Disconnect the harness connector at the K36 SDM.
2. Test for infinite resistance between the seat belt switch signal circuit terminal 4 and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
3. Test for less than 2 ohm in each control circuit end to end.
• If 2 ohm or greater, repair the open/high resistance in the circuit.
• If less than 2 ohm, replace the K36 SDM.
• If test lamp turns on and off while changing between the commanded states
7. Replace the P14 passenger air bag disable indicator.
Component Testing
1. Ignition OFF.
2. Disconnect the harness connector at the appropriate B88 passenger seat belt switch.
3. B88 seat belt buckle in the open position.
4. Test for infinite resistance between the signal circuit terminal A and the ground terminal B at the B88 passenger seat belt switch.
• If there is not infinite resistance
• Replace the B88 passenger seat belt switch.
• If there is infinite resistance
5. B88 seat belt switch in the closed position.
6. Test for less than 2 ohm between the signal circuit terminal A and the ground terminal B at the B88 passenger seat belt switch.
• If 2 ohm or greater
• Replace the B88 passenger seat belt switch.
• If less than 2 ohm
7. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Inflatable Restraint Instrument Panel Module Indicator Replacement Service and Repair
* Inflatable Restraint Front Passenger Presence Sensor Replacement Service and Repair
* Front Seat Belt Buckle Replacement Front Seat Belt Buckle Replacement
* Control Module References Control Module References for SDM replacement, setup, and programming