Vented Seat Malfunction
Vented Seat Malfunction
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
The driver and passenger vented seats are controlled by separate vented seat switches. Both switches are located in the climate control panel (CCP). When a vented seat switch is pressed, the CCP sends a GMLAN message via the serial data line to the memory seat module (MSM) indicating the vented seat command. In response to this message, the MSM then sends a pulse width modulation (PWM) signal through the vented seat mode signal circuit to the appropriate seat blower motors indicating the vented seat command. In response to this signal, the logic in the blower motors set the blower speed to the switch set point. Both blower motors then run drawing cabin air around and away from occupant.
Reference Information
Schematic Reference
Heated/Cooled Seat Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Heated/Vented Seat Description and Operation (Description and Operation)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
Scan Tool Reference
Control Module References (Programming and Relearning) for Scan Tool Information
Circuit/System Verification
1. Ignition ON, observe the scan tool HVAC Driver Seat Vent Sw. parameter while pressing the driver VENTED seat switch. The readings should change between Inactive and Active.
• If not the specified value, replace the HVAC Control Module.
2. If the scan tool displays normal and the driver vented seat is inoperative, refer to Circuit/System Testing.
3. Observe the scan tool HVAC Psgr. Seat Vent Sw. parameter while pressing the passenger VENTED seat switch. The readings should change between Inactive and Active.
• If not the specified value, replace the HVAC Control Module.
4. If the scan tool displays normal and the passenger vented seat is inoperative, refer to Circuit/System Testing.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the inoperative blower motor(s).
2. Ignition OFF, test for less than 5 ohms between the ground circuit terminal B and ground.
• If greater than the specified value, test the ground circuit for an open/high resistance.
3. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal C and ground.
• If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
4. Connect a test lamp between the signal circuit terminal A and battery voltage.
5. Press the VENTED seat switch through the high, medium, and low positions to OFF. The test lamp should illuminate until the OFF position is reached.
• If the test lamp does not illuminate, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the MSM.
• If the test lamp is ON with the switch in the OFF position, test the signal circuit for a short to ground. If the circuit tests normal, replace the MSM.
6. If all circuits test normal, test or replace the blower motor.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Driver Seat and Passenger Seat Back Ventilation Heating and Cooling Blower Replacement (Driver Seat and Passenger Seat Back Ventilation Heating and Cooling Blower Replacement)
* Driver Seat and Passenger Seat Cushion Ventilation Heating and Cooling Blower Replacement (Driver Seat and Passenger Seat Cushion Ventilation Heating and Cooling Blower Replacement)
* Control Module References (Programming and Relearning) for HVAC control module and MSM replacement, setup, and programming