Heated Seat Inoperative
Heated Seat Inoperative
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
Battery positive voltage is supplied at all times to the heated seat module through the battery positive voltage circuit and the HTD SEATS fuse located in the underhood fuse block. 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 G301.
When the heated seat switch is placed in either the high or low temperature position, battery positive voltage is applied through the heated seat switch signal circuit to the heated seat module. At the same time, battery voltage is also applied through one of two resistors in the switch and the heated seat HI/LO signal circuit to the module. In response to these switch signals, the heated seat module closes its contacts and applies battery positive voltage through the heated seat element supply voltage to the seat heating elements. When the heated seat switch is in the HIGH heat position, battery voltage is applied through a 200 ohm resistor and the module sets the seat temperature to high heat. When the heated seat switch is in the LOW heat position, battery voltage is applied through a 2,850 ohm resistor and the module sets the seat temperature to low heat.
Circuit/System Verification
1. Ignition ON, cycle the heated seat switch between the high and low position. The heated seats should operate in both positions.
^ If the heated seats do not operate, refer to Heated Seats Inoperative.
2. Cycle the heated seat switch between the high and low position. The appropriate heated seat indicator should illuminate.
^ If either indicator does not illuminate refer to Headed Seat Indicator Inoperative.
Circuit/System Testing
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 D 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 at the appropriate heated seat module.
4. Test for less than 1 ohm between the ground circuit terminal 4 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 5 and ground.
^ If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
6. Place the heated seat switch in the high position. Verify that a test lamp illuminates between the signal circuit terminal 8 and ground.
^ If the test lamp does not illuminate, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the heated seat switch.
7. Place the heated seat switch in the low position. Verify that a test lamp illuminates between the signal circuit terminal 8 and ground.
^ If the test lamp does not illuminate, test or replace the heated seat switch.
8. Place the heated seat switch in the high position. Test for B+ between the signal circuit terminal 3 and ground.
^ If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the heated seat switch.
9. Place the heated seat switch in the low position. Test for B+ between the signal circuit terminal 3 and ground.
^ If not the specified value, test or replace the heated seat switch.
10. Ignition OFF, disconnect the harness connector at the heated seat element - cushion.
11. Test for less than 1 ohm between the ground circuit terminal C and ground.
^ If greater than the specified range, test the ground circuit for an open/high resistance.
12. Test for less than 5 ohms between the control terminal D and ground.
^ If not within the specified range, test the following circuits for a short to ground or an open/high resistance.
* Control circuit between the heated seat element - cushion terminal D and the heated seat element - back terminal A.
* Heated seat element - back ground circuit terminal B and ground If the circuits test normal, test or replace the heated seat element - back.
13. Connect the harness connector at the heated seat element - cushion.
14. Test for less than 10 ohms between the control circuit terminal 7 and ground.
^ If not within the specified range, test the control circuit for a short to ground or open/high resistance. If the circuits test normal, test or replace the Heated Seat Element - Cushion
15. Test for 1200-10K ohms between the control circuit terminal 6 and ground.
^ If not within the specified range, test the control circuit for a short to ground or open/high resistance. If the circuits test normal, test or replace the Heated Seat Element - Cushion.
16. If all circuits test normal, replace the heated seat module.
Heated Seats Indicator Circuit Inoperative
1. Ignition OFF, disconnect the harness connector at the appropriate heated seat switch.
2. Test for less than 1 ohm between the ground circuit terminal E and ground.
^ If greater than the specified range, test the ground circuit for an open/high resistance.
3. If all circuits test normal, replace the heated seat switch.
Component Testing
Heated Seat Switch
1. Ignition OFF, disconnect the harness connector at the appropriate heated seat switch.
2. Test for infinite resistance between the heated seat switch terminal A and terminal D.
^ If not the specified value, replace the switch.
3. Test for infinite resistance between the heated seat switch terminal F and terminal D.
^ If not the specified value, replace the switch.
4. Place the switch in the low position. Test for 2,800-2,900 ohms between terminal A and terminal D.
^ If not within the specified range, replace the switch.
5. Place the switch in the high position. Test for 180-220 ohms between terminal A and terminal D.
^ If not within the specified range, replace the switch.
6. Place the switch in the high position. Test for less than 2 ohms between terminal F and terminal D.
^ If greater than specified range, replace the switch
7. Place the switch in the low position. Test for less than 2 ohms between terminal F and terminal D.
^ If greater than specified range, replace the switch
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
* Heated Seat Switch Replacement
* Driver Seat and Passenger Seat Back Cushion Heater Replacement
* Driver Seat and Passenger Seat Cushion Heater Replacement