Heated Seat Inoperative

Heated Seat Inoperative

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 Instructionsprovides 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 on the HVAC panel. When a heated seat switch is pressed, a serial data message is sent from the HVAC control module to the memory seat module (MSM) indicating the heated seat request. In response to this message, the MSM applies battery positive voltage through the element supply voltage circuit to the appropriate seat heating elements. The module controls the seat temperature by providing a PWM ground through the heated seat element control circuits to the seat heater elements. The MSM then sends a serial data message back to the HVAC control module to either illuminate or turn off the appropriate temperature indicators.

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

Heated Seats Description and Operation
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 Relearningfor scan tool information

Circuit/System Verification

1. Ignition ON, observe the appropriate scan tool Seat 1 or 2 HVC Data parameters listed below while pressing and releasing the appropriate switch. The readings should change from Off to Back and Cushion or Back Only.

* Driver Seat HVC Mode
* Passenger Seat HVC Mode

• If not the specified values and there are no DTCs set, replace the HVAC control module.

2. If all scan tool parameters test normal and there are no DTCs set, replace the MSM.

Repair Instructions

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

Control Module References Programming and Relearningfor memory seat module and HVAC control module replacement, programming, and setup