Seat Belt Indicator Circuit Malfunction - Rear
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Seat Belt Indicator Circuit Malfunction - Rear
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Diagnostic Fault Information
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Circuit
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Short to Ground
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High Resistance
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Open
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Short to Voltage
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Signal Performance
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Rear Seat Belt Switch Signal
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1
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2
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2
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2
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-
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Rear Seat Belt Switch Low Reference
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-
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2
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2
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2
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-
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1. Green indicator will illuminate only for the bulb check. The red indicator will remain ON with seat belt buckled.
2. Green indicator will illuminate only for the bulb check. The red indicator will never illuminate.
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Circuit/System Description
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All three rear seat belt switches are 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.
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
Scan Tool Reference
Control Module References
for scan tool information
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1.
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The mechanical stop in the buckle may prevent latching but the switch in the buckle may momentarily open and the SDM would interpret this as an occupant in the rear seat position and that the buckle was attempting to latch.
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2.
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If a rear occupant attempts to latch the seat belt into the wrong buckle, the indicatormay illuminate and the system assumes there is an occupant not buckled in that seat position.
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3.
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An unseated connector can appear as a buckled seat belt connection.
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Circuit/System Verification
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1.
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1. Verify that all connectors are fully seated.
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2.
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With the scan tool monitor the 2nd Row 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.
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1.
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Note
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When removing connectors inspect for damage or corrosion. Damage or corrosion in the following requires repair or replacement of the affected component/connector.
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•
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B88 Seat belt switch
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•
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Seat belt switch harness connector
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•
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K36 SDM
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•
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SDM wiring harness connector
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Ignition OFF, disconnect the harness connector at the B88 seat belt switch.
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2.
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Test for less than 5 Ω between the ground circuit terminal 2 and ground.
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3.
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If greater than the specified range, test the ground circuit for an open/high resistance. If the circuit tests normal replace the K36 SDM.
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4.
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Ignition ON, verify the scan tool 2nd Row Seat Belt Status parameter displays Buckled.
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5.
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If not the specified value, test the signal circuit terminal A for a short to ground. If the circuit tests normal replace the K36 SDM.
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6.
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Install a 3 A fused jumper wire between the circuit terminal 1 and the ground circuit terminal 2. Verify the scan tool 2nd Row Seat Belt Status parameter displays Unbuckled.
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7.
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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 K36 SDM.
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1.
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Ignition OFF, disconnect the harness connector at the B88 seat belt switch.
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2.
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Test for infinite resistance between the signal circuit terminal 1 and the ground terminal 2, at the switch, with the switch in the open position.
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4.
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Test for less than 5 Ω between the signal circuit terminal 1 and the ground terminal 2, at the switch, with the switch in the closed position.
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Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
Control Module References
for SDM and driver information center, setup, and programming
