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 Instructions)provides an overview of each diagnostic category.



Circuit/System Description

The heated seat control module controls the battery positive voltage used to supply the seat heater elements. Ignition voltage is supplied to the heated seat switch from the HVAC 20A fuse in the underhood BEC. When the heated seat switch is in the high or low positions voltage is supplied through one of the internal resistors to the switch signal circuit.


Reference Information
Schematic Reference

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

Component Connector End Views (Component Connector End 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)for Scan Tool Information


Circuit/System Verification


Driver Seat
1. Ignition ON, turn the heated seat switch from off to the high and low positions. The heated seat switch indicator should be illuminated while the switch is in the high and low positions.

• If the heated seat switch indicator does not illuminate or is always illuminated refer to the driver heated seat switch circuit test.

2. If the heated seat switch indicator operates normal, refer to the heated seat circuit test.



Passenger Seat
1. Ignition ON, seat belt buckled, turn the heated seat switch from off to the high and low positions. The heated seat switch indicator should be illuminated while the switch is in the high and low positions.

• If the heated seat switch indicator does not illuminate or is always illuminated refer to the passenger heated seat switch circuit test.

2. If the heated seat switch indicator operates normal, refer to the heated seat circuit test.



Circuit/System Testing


Driver Heated Seat Switch Circuit Test
1. Ignition OFF, disconnect the harness connector at the heated seat switch.
2. Test for less than 1 ohm of resistance between the ground circuit terminal E and ground.

• If greater than the specified range, 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. If all circuits test normal, test or replace the heated seat switch.



Passenger Heated Seat Switch Circuit Test
1. Ignition OFF, disconnect the harness connector at the heated seat switch.
2. Test for less than 1 ohm of resistance between the ground circuit terminal E and ground.

• If greater than the specified range, 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 ignition circuit terminal C and the seat belt switch signal circuit terminal D.
5. Buckle and unbuckle the seat belt. The test lamp should be off when buckled and on when unbuckled.

• If the test lamp is always on, test the seat belt switch signal circuit for a short to ground. If the circuit tests normal, replace the seat belt buckle.


• If the test lamp is always off, test the seat belt switch signal circuit for an open/high resistance. If the circuit tests normal, replace the seat belt buckle.

6. If all circuits test normal, test or replace the heated seat switch.
7. Test for less than 1 ohm of resistance between the ground circuit terminal 4 and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.




Heated Seat Circuit Test
1. Ignition OFF, disconnect the harness connector at the heated seat module.
2. Test for less than 1 ohm of resistance between the ground circuit terminal 4 and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Verify that a test lamp illuminates between the B+ circuit terminal 5 and ground.

• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

4. Test for infinite resistance between the heated seat switch signal circuit terminal 6 and the ground circuit terminal 4.

• If less than the specified value, test the switch signal circuit for a short to ground. If the circuit tests normal, replace the heated seat switch.

5. Switch in the high position, test for approximately 2.5K ohms of resistance between the heated seat switch signal circuit terminal 6 and the ground circuit terminal 4.

• If not the specified value, test the switch signal circuit for an open/high resistance. If the circuit tests normal, replace the heated seat switch.

6. Switch in the low position, test for approximately 4.9K ohms of resistance between the heated seat switch signal circuit terminal 6 and the ground circuit terminal 4.

• If not the specified value replace the heated seat switch.

7. Test for 5 - 15K ohms of resistance between the thermistor signal circuit terminal 2 and the ground circuit terminal 4.

• If not within the specified range, replace the seat cushion heater element.

8. Disconnect the seat back heater element connector.
9. Test for 1.0 - 10 ohms of resistance through the seat back heater element.

• If not within the specified range, replace the seat back heater element.

10. Test for 1.0 - 10 ohms of resistance between the heated seat module connector terminal 7 and the seat back heater element connector terminal A.

• If not within the specified range, replace the seat cushion heater element.

11. If all circuits test normal, replace the heated seat module.



Repair Instructions

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

* Driver or Passenger Seat Back Cushion Heater Replacement (Driver or Passenger Seat Back Cushion Heater Replacement)
* Driver or Passenger Seat Cushion Heater Replacement (Driver or Passenger Seat Cushion Heater Replacement)