Grand Cherokee 4WD V8-4.7L VIN N (2000)
Seat Heater Thermostat: Service and Repair
Heated Seat Sensor Test
1. Disconnect and isolate the battery negative cable. Disconnect the 4-way heated seat cushion element wire harness connector from the power seat
wire harness. The power seat wire harness connectors for the seat cushion and seat back heating elements are secured to a bracket located under
the rear edge of the seat cushion frame.
2. Check for continuity between the seat sensor 5V supply circuit cavity of the 4-way heated seat cushion element wire harness connector and the seat
cushion frame. There should be no continuity. If OK, go to Step 3. If not OK, replace the faulty seat cushion cover trim and element unit.
3. Using an ohmmeter, check the resistance between the seat sensor 5V supply circuit and the seat temperature sensor input circuit cavities of the
4-way heated seat cushion element wire harness connector. The sensor resistance should be between 14 kilohms at 15 °C (60 °F) and 5 kilohms
at 30 °C (85 °F). If OK, go to Step 4, If not OK, replace the faulty seat cushion cover trim and element unit.
4. Disconnect the C1 connector of the power seat wire harness from the Heated Seat Module (HSM) or Memory Heated Seat Module (MHSM)
connector receptacle. Check for continuity between the seat sensor 5V supply circuit cavity of the 4-way power seat wire harness connector for the
heated seat cushion element and the seat cushion frame. There should be no continuity. If OK, go to Step 5. If not OK, repair the shorted seat
sensor 5V supply circuit as required.
5. Check for continuity between the seat sensor 5V supply circuit cavities of the 4-way power seat wire harness connector for the heated seat cushion
element and the C1 power seat wire harness connector for the HSM or MHSM. There should be continuity. If OK, go to Step 6. If not OK, repair
the open seat sensor 5V supply circuit as required.
6. Check for continuity between the seat temperature sensor input circuit cavity of the 4-way power seat wire harness connector for the heated seat
cushion element and the seat cushion frame. There should be no continuity If OK, go to Step 7. If not OK, repair the shorted seat temperature
sensor input circuit as required.
7. Check for continuity between the seat temperature sensor input circuit cavities of the 4-way power seat wire harness connector for the heated seat
cushion element and the C1 power seat wire harness connector for the HSM or MHSM. There should be continuity. If OK, refer to Heated Seat
Module. If not OK, repair the open seat temperature sensor input circuit as required.
