Battery positive voltage is supplied at all times to the heated seat module from the HTD SEAT fuse located in the rear fuse block. Ignition voltage is supplied to the heated seat switch and the heated seat module from the ROOF/HEAT SEAT fuse located in the BCM. When commanded ON, the heated seat module uses this voltage to heat the seat heating elements. The heated seat module and the seat heating elements are grounded through the module ground circuit to G303.

Each time the heated seat switch is pressed, B+ is supplied to the heated seat module through the heated seat signal circuit. The module counts these inputs to determine what level of heat the vehicle operator is commanding. In response to these switch signals, the heated seat module closes it's contacts and applies battery positive voltage through the heated seat element supply voltage circuit to the seat heating elements. When the thermistor inside the seat cushion reaches a certain resistance, the control module open and close the supply voltage in order to maintain that heat level.

Schematic Reference

Heated/Cooled Seat Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Heated Seats Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Heated Seats Inoperative

1. Ignition OFF, disconnect the harness connector at the appropriate heated seat switch.
2. Ignition ON, 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.

3. Ignition OFF, connect the harness connector at the heated seat switch. Disconnect the harness connector C1 at the appropriate heated seat module.
4. Test for less than 1 ohm of resistance between the ground circuit terminal 1 and ground.

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

5. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 4 and ground.

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

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

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

7. Press and release the heated seat switch. Verify that a test lamp illuminates between the control circuit terminal 2 and ground each time the switch is pressed.

⇒	If the test lamp does not illuminate when the switch is pressed, test the signal circuit for a short to ground or an open/high resistance. If the circuit test normal test or replace the switch.

⇒	If the test lamp remains illuminated, test the control circuit for an short to voltage. If the circuit test normal test or replace the switch.

8. Ignition OFF, connect the harness connector at the heated seat module. Disconnect the harness connector at the appropriate heated seat element-cushion.
9. Place the heated seat switch in the ON position. Verify that a test lamp illuminates between the supply voltage circuit terminal and ground.

⇒	If the test lamp does not illuminate, test the supply voltage circuit for a short to ground or an open/high resistance.

10. Place the heated seat switch in the ON position. Verify that a test lamp illuminates between the control circuit terminal and B+.

⇒	If the test lamp does not illuminate, test the control circuit for a short to voltage or an open/high resistance. If the circuit test normal, test or replace the heated seat element-cushion.

11. Ignition OFF, connect the harness connector at the heated seat module. Disconnect the harness connector at the appropriate heated seat element-cushion.
12. Place the heated seat switch in the ON position. Verify that a test lamp illuminates between the supply voltage circuit terminal and ground.

⇒	If the test lamp does not illuminate, test the supply voltage circuit for a short to ground or an open/high resistance.

13. Place the heated seat switch in the ON position. Verify that a test lamp illuminates between the control circuit terminal and B+.

⇒	If the test lamp does not illuminate, test the control circuit for a short to voltage or an open/high resistance. If the circuit test normal, test or replace the heated seat element-cushion.

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.