Rear Heated Seat Malfunction

Rear Heated Seat Malfunction

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information





Circuit/System Description

The left and right rear heated seats are controlled by separate heated seat switches located in the auxiliary radio/HVAC controls. When a heated seat switch is pressed, a serial data message is sent to the rear seat control module indicating the heated seat command. In response to this message, the rear seat heating control module applies battery positive voltage through the element control circuit to the appropriate seat heating elements. The rear seat heating control module then sends a serial data message back to the auxiliary radio/HVAC controls to either illuminate or turn off the heated seat indicator.

Reference Information
Schematic Reference

Heated/Cooled Seat Schematics ([1][2]Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector End Views By Name)
Description and Operation

Rear Heated Seats Description and Operation (Rear Heated Seats)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

1. Engine ON, observe the scan tool Left Rear Seat Heating/Venting/Cooling Mode parameter while pressing the left rear HEATED seat switch. The reading should change between Off and Back & Cushion Heat.

• If not the specified value, replace the A21 auxiliary radio/HVAC controls.

2. Observe the scan tool Right Rear Seat Heating/Venting/Cooling Mode parameter while pressing the right rear HEATED seat switch. The reading should change between Off and Back & Cushion Heat.

• If not the specified value, replace the A21 auxiliary radio/HVAC controls.

3. If all scan tool parameter readings test normal, there are no DTCs set, and the left and/or right rear heated seat is inoperative, replace the K29R rear seat heating control module.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Heater and Air Conditioning and Radio Control Module Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for rear seat heating control module and body control module replacement, setup, and programming