Front Heated Seat Malfunction
Front Heated 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.
Circuit/System Description
Battery voltage is supplied at all times to the heated seat modules through the DRVR HTD SEAT fuse and the PASS HTD SEAT fuse located in the IP fuse block. This voltage is used by each module to supply power to the seat cushion and seat back heating elements. Each heated seat module is also supplied with battery voltage through the HTD SEAT/WPR RLY fuse located in the body control module (BCM) which is controlled by the RUN CRANK relay. This voltage is used to power up each heated seat module and allows the heated seat system to operate only with the ignition in the ON position. Each heated seat module is grounded through the module ground circuit at G301 for the driver seat and G302 for the passenger seat.
Reference Information
Schematic Reference
Heated/Cooled Seat Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Heated Seats 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)
Circuit/System Testing
1. Ignition OFF, disconnect the X1 harness connector at the inoperative heated seat module.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the heated seat module ground circuit terminal K.
• If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
3. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal A and ground.
• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
4. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal B and ground.
• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
5. Ignition ON, verify that a test lamp does not illuminate between B+ and the heated seat module inhibit signal circuit terminal G.
• If the test lamp illuminates, test the signal circuit terminal G for a short to ground. If the circuit tests normal, replace the HVAC control module.
6. Ignition OFF, disconnect the harness connector at the inoperative heated seat switch.
7. Ignition OFF, verify that a test lamp illuminates between B+ and the heated seat switch ground circuit terminal 3.
• If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
8. Connect the harness connector at the inoperative heated seat switch.
9. Ignition OFF, connect a test lamp between B+ and the appropriate heated seat high/low signal circuit terminal D.
10. Operate the heated seat HI/LO switch ON and OFF. The test lamp should turn ON and OFF as the switch is operated.
• If the test lamp is always ON, test the signal circuit terminal D for a short to ground. If the circuit tests normal, replace the heated seat switch.
• If the test lamp is always OFF, test the signal circuit terminal D for a short to voltage or and open/high resistance. If the circuit tests normal, replace the heated seat switch.
11. Connect a test lamp between B+ and the appropriate heated seat switch off signal circuit terminal F.
12. Operate the heated seat OFF switch ON and OFF. The test lamp should turn ON and OFF as the switch is operated.
• If the test lamp is always ON, test the signal circuit terminal F for a short to ground. If the circuit tests normal, replace the heated seat switch.
• If the test lamp is always OFF, test the signal circuit terminal F for a short to voltage or and open/high resistance. If the circuit tests normal, replace the heated seat switch.
13. Connect the X1 harness connector at the inoperative heated seat module.
14. Disconnect the X2 harness connector at the appropriate heated seat module.
15. Ignition OFF, seat COOLED, test for between 850-11,500 ohms of resistance between the temperature sensor low reference circuit terminal D and temperature sensor signal circuit terminal F.
• If greater than the specified range, test the low reference and signal circuits for a short to voltage or an open/high resistance. If the circuits test normal, test or replace the appropriate heated seat cushion.
• If less than the specified range, test the low reference and signal circuits for a short to ground. If the circuits test normal, test or replace the appropriate heated seat cushion.
16. Disconnect the harness connector at the appropriate heated seat cushion.
17. Test for less than 8.0 ohms of resistance between terminal D and terminal C at the seat cushion element.
• If greater than the specified range, replace the appropriate heated seat cushion.
18. Connect the harness connector at the heated seat cushion.
19. Disconnect the harness connector at the appropriate heated seat back.
20. Test for less than 8.0 ohms of resistance between terminal A and terminal B at the seat back element.
• If greater than the specified range, replace the appropriate heated seat back.
21. Connect the harness connector at the heated seat back.
22. Test for less than 8.0 ohms of resistance between the heated seat element voltage circuit terminal A and the element control circuit terminal C.
• If greater than the specified range, test the voltage and control circuits for a short to voltage or an open/high resistance.
• If less than the specified range, test the voltage and control circuits for a short to ground.
23. If all circuits test normal, replace the inoperative heated seat module.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Front Seat Heater Control Module Replacement (Service and Repair)
* Driver Seat and Passenger Seat Back Cushion Heater Replacement (Driver Seat and Passenger Seat Back Cushion Heater Replacement)
* Driver Seat and Passenger Seat Cushion Heater Replacement (Driver Seat and Passenger Seat Cushion Heater Replacement)
* Heated Seat Switch Replacement (Service and Repair)
* Control Module References (Programming and Relearning)for heated seat module and HVAC control module replacement, setup, and programming