LaCrosse FWD L4-2.4L (2011)
Seat Heater: Testing and Inspection
Vented Seat Malfunction
Vented Seat Malfunction
Diagnostic Instructions
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Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
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Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
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Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure Instructions)
provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
With the ignition in the ON position, ignition voltage is applied to the ignition main relay energizing the relay. With the relay energized, battery voltage
is applied through the switch side of the relay, the 10 A DSM fuse, and the ignition circuit to the driver and passenger vented seat blower motors. The
driver and passenger vented seats are controlled by separate vented seat switches located in the radio/HVAC controls. When a vented seat switch is
pressed, a serial data message is sent from the radio/HVAC controls to the HVAC control module indicating the vented seat command. The HVAC
control module serves as a gateway to transmit the message to the seat memory control module via the serial data line. In response to this message, the
seat memory control module applies a low side pulse width modulation (PWM) signal through the blower motor control circuits to the seat cushion and
seat back blower motors indicating the vented seat command. The logic in the blower motors then sets the blower speed to the switch set point. Both
blower motors run drawing cabin air around and away from occupant. The seat memory control module then sends a serial data message back to the
HVAC control module to gateway the information back to the radio/HVAC controls to either illuminate or turn off the appropriate switch indicator.
Reference Information
Schematic Reference
Heated/Cooled Seat Schematics (See: Diagrams/Electrical Diagrams)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views/Connector End Views By Name)