Buick Regal: Symptoms - Seat Belts
NOTE: Review the seat belt system description and operation in order to
familiarize yourself with the system and how it functions.
Visual/Physical Inspection
- Inspect for aftermarket devices which could affect the operation of the
seat belt system. Refer to Checking Aftermarket Accessories.
- Inspect the easily accessible or visible system components for obvious
damage or conditions
which could cause the symptom.
Intermittent
Faulty electrical connections or wiring may be the cause of intermittent
conditions. Refer to Testing for Intermittent Conditions and Poor Connections.
Symptom List
Refer to the following symptom diagnostic procedure in order to diagnose the
symptom:
- Seat Belt Indicator Malfunction - Driver
- Seat Belt Indicator Malfunction - Passenger
SEAT BELT INDICATOR MALFUNCTION - DRIVER
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
1. Seat Belt Indicator Always Illuminated
2. Seat Belt Indicator Inoperative
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 Wiring Schematics
- SIR Wiring Schematics
Connector End View Reference
COMPONENT CONNECTOR END VIEWS - INDEX
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. 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
commanded
Replace the P16 instrument cluster.
- Go to next step: If the driver seat belt indicator does turn ON and
OFF as commanded
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.
- If the scan tool Driver Seat Belt Switch parameter does not display
Buckled and
Unbuckled when changing seat belt states
Refer to Circuit/System Testing.
- Go to next step: If the scan tool Driver Seat Belt Switch parameter
does display
Buckled and Unbuckled when changing seat belt states
3. All OK.
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.
- B88 Seat belt switch
- Seat belt switch harness connector
- K36 SDM
- SDM wiring harness connector
1. Ignition OFF.
2. Disconnect the harness connector at the B88 seat belt switch.
3. Test for less than 10 Ω between the low reference circuit terminal 1 and
ground.
- Disconnect the harness connector at the K36 SDM.
- 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.
- Go to next step: If less than 10 Ω
4. Ignition ON.
5. Verify the scan tool Driver Seat Belt Status parameter displays Buckled.
- If the scan tool Driver Seat Belt Status parameter does not display
Buckled
- Disconnect the harness connector at the K36 SDM.
- 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 Ω, replace the K36 SDM.
- Go to next step: If the scan tool Driver Seat Belt Status parameter
does display
Buckled
6. Install a 3 A fused jumper wire between the signal circuit terminal 2 and
the low reference circuit
terminal 1.
7. Verify the scan tool Driver Seat Belt Status parameter displays Unbuckled.
- If the scan tool Driver Seat Belt Status parameter does not display
Unbuckled
- Disconnect the harness connector at the K36 SDM.
- Ignition ON.
- 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.
- 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.
- Go to next step: If the scan tool Driver Seat Belt Status parameter
does display
Unbuckled
8. Replace the B88 seat belt switch.
Component Testing
1. Ignition OFF.
2. Disconnect the harness connector at the B88 seat belt switch.
3. B88 seat belt switch in the open position.
4. Test for infinite resistance between the signal circuit terminal 2 and the
low reference terminal 1 at
the B88 seat belt switch.
- If there is not infinite resistance
Replace the B88 seat belt switch.
- Go to next step: If there is infinite resistance
5. B88 seat belt switch in the closed position.
6. Test for less than 1 Ω between the signal circuit terminal 2 and the low
reference terminal 1 at the
B88 seat belt switch.
Replace the B88 seat belt switch.
- Go to next step: If less than 1 Ω
7. All OK.
Repair Instructions
- Perform the Diagnostic Repair Verification after completing the
diagnostic procedure.
- Front Seat Belt Buckle Replacement
- Control Module References for SDM and instrument cluster replacement,
programming and
setup
READ NEXT:
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.
Diag
REPAIRS AND INSPECTIONS REQUIRED AFTER A COLLISION
WARNING: Restraint systems can be damaged in a collision. To help
avoid injury and ensure that all parts in need of replacement are replaced:
Repl
SEAT BELT SYSTEM DESCRIPTION AND OPERATION
Seat Belts
Solid Line - Hard Wire I/O
Dash Line - Serial Data
A11 - Radio
B88D - Seat Belt Switch - Driver
B88P - Seat Belt Switch - Passenger
K36 - Inflata
SEE MORE:
OnStar Smart Driver provides
information about driving behavior to
help maximize overall vehicle
performance, reduce wear and tear,
and enhance fuel efficiency. An
Insurance Discounts Eligibility
feature is also offered within OnStar
Smart Driver. See www.onstar.com
for details regarding vehicle
eli
Diagnostic Instructions
Perform the Diagnostic System Check prior to using this diagnostic
procedure:Diagnostic System
Check - Vehicle
Review the description of Strategy Based Diagnosis:Strategy Based
Diagnosis
An overview of each diagnostic category can be found here:Diagnostic
Procedure