Chevrolet Trax: Front heated seat malfunction (with memory A45)

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

Circuit/System Description

The driver and front passenger heated seats are controlled by separate heated seat switches that are located in the radio/HVAC controls. When a heated seat switch is pressed, a serial message is sent from the radio/HVAC controls to the HVAC control module indicating the heated seat command. The HVAC control module then 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 battery positive voltage through the element supply voltage circuit to the appropriate seat heating elements. The seat memory control module then sends a serial data message back to the HVAC control module to gateway the information to the radio/HVAC controls to either illuminate or turn off the appropriate temperature indicator.

Reference Information

Schematic Reference

Heated/Cooled Seat Schematics (Encore), Heated/Cooled Seat Schematics (Trax)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX

Description and Operation

Heated Seats 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. Engine ON.
2. Verify that no heated seat DTCs are set.

• If any heated seat DTC is set

Refer to Diagnostic Trouble Code (DTC) List - Vehicle

• If no heated seat DTCs are set

3. Verify the scan tool Front Seat Heating Control Module Driver Seat Heating/Venting/Cooling Mode parameter changes between Off and Back & Cushion Heat after pressing the driver heated seat switch.

• If the parameter does not change

Replace the K33 HVAC Control Module.

• If the parameter changes

4. Verify the scan tool Passenger Front Seat Heating/Venting/Cooling Mode Switch parameter changes between Off and Back & Cushion Heat after pressing the passenger heated seat switch.

• If the parameter does not change

Replace the K33 HVAC Control Module.

• If the parameter changes

5. Refer to Circuit/System Testing.

Circuit/System Testing

1. Ignition OFF, disconnect the X4 harness connector at the K40 Seat Memory Control Module, ignition ON.
2. Verify a test lamp illuminates between the B+ circuit terminal 5 and ground.

If the test lamp does not illuminate

1. Ignition OFF.
2. Test for less than 2 ohms in the B+ circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse.
• If the test lamp illuminates

3. Ignition OFF, connect the X4 harness connector at the K40 Seat Memory Control Module, ignition ON,
4. Verify the scan tool Seat Memory Control Module Driver Seat Heating/Venting/Cooling Mode parameter changes between Off and Back & Cushion Heat after pressing the driver heated seat switch.

• If the parameter does not change

Replace the A20 Radio/HVAC Controls.

• If the parameter changes

5. Verify the scan tool Passenger Front Seat Heating/Venting/Cooling Mode parameter changes between Off and Back & Cushion Heat after pressing the passenger heated seat switch.

• If the parameter does not change

Replace the A20 Radio/HVAC Controls.

• If the parameter changes

6. Replace the K40 Seat Memory Control Module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Radio Control Assembly Replacement
• Control Module References for K40 Seat Memory Control Module replacement, programming and setup

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