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Circuit/System Verification
Ignition ON, perform the IPC Display Test using the scan
tool and verify the driver seat belt indicator is illuminated.
➢ If the indicator does not illuminate, replace the IPC.
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.
• The BCM
• The left seat belt switch
• The SDM
• The left seat belt switch harness connector
• The SDM wiring harness connector
1. Ignition OFF, disconnect the harness connector at
the left seat belt switch.
2. Ignition OFF, test for less than 1.0 ohm of resistance
between the low reference circuit terminal A and
ground.
➢ If greater than the specified value, test the low
reference circuit for an open/high resistance. If the
circuit tests normal, replace the SDM.
3. Ignition ON, verify the scan tool driver seat belt
switch parameter is Unbuckled.
➢ If not the specified value, test the signal circuit
terminal for a short to ground. If the circuit tests
normal replace the SDM.
4. Install a 3-amp fused jumper wire between the signal
circuit terminal B and the low reference circuit
terminal A. Verify the scan tool driver seat belt switch
parameter is Buckled.
➢ 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 SDM.
5. If all circuits test normal, replace the left seat belt
switch.
Component Testing
1. Ignition OFF, disconnect the harness connector at
the left seat belt switch.
2. Test for infinite resistance between the signal circuit
terminal B and the low reference terminal A.
➢ If not the specified value, replace the left seat belt
switch.
3. With the seat belt buckled, test for less than 2 ohms
of resistance between the signal circuit terminal B
and the low reference terminal A.
➢ If greater than the specified range, replace the left
seat belt switch.
Repair Instructions
Perform the "Diagnostic Repair Verification - Vehicle
Diagnostic Information: " after completing the diagnostic
procedure.
• "Front Seat Belt Buckle Replacement"
• "Control Module References: " for SDM and IPC
replacement, setup, and programming
Seat Belt Indicator Circuit Malfunction -
Passenger
Diagnostic Fault Information
Perform the "Diagnostic System Check - Vehicle
Diagnostic Information: " prior to using this diagnostic
procedure.
Circuit/System Description
The inflatable restraint sensing and diagnostic module
(SDM) sends the status of the passenger seat belt
switch to the instrument panel cluster (IPC) via the
GMLAN serial data communication line. The IPC
controls power to the passenger seat belt indicator to
turn the indicator on/off. The SDM will only send a
command to the IPC to turn the indicator on when the
seat belt is unbuckled and the SDM senses an occupant
in the passenger seat.
Reference Information
Schematic Reference
• "Seat Belt Schematics"
• "SIR Schematics: "
Connector End View Reference
"Seat Belt 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
• "Scan Tool Data List - SIR: "
• "Scan Tool Data Definitions - SIR: "
Seat Belts:
8A-9
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Table of Contents
Troubleshooting
