HEATED SEAT SENSOR
DESCRIPTION
The heated seat temperature sensor is a Negative Temperature Coefficient (NTC) thermistor. One temperature sensor is used for each seat. This temperature sensor is located in the seat cushion heating element on all models.
The heated seat temperature sensor cannot be repaired or adjusted and must be replaced if defective. The heated seat cushion element must be replaced if the temperature sensor is defective. Refer to the procedure in this section of the service manual.
OPERATION
When the temperature of the seat cushion cover rises, the resistance of the sensor decreases. The heated seat module supplies five-volts to one side of each sensor, and monitors the voltage drop through the sensor on a return circuit. The heated seat module uses this temperature sensor input to monitor the temperature of the seat, and regulates the current flow to the seat heating elements accordingly.
DIAGNOSIS AND TESTING - HEATED SEAT SENSOR
For complete circuit diagrams, refer to WIRING.
NOTE: Any resistance values (ohms Ω) given in the following text are supplied using the automatic range generated by a fluke® automotive meter. If another type of measuring device is used the values generated may not be the same as the results shown here, or may have to be converted to the range used here.
1. Position the driver seat in the full rearward position.
2. Unclip the heated seat module from the bottom of the drivers seat cushion pan.
3. Back-probe the heated seat module wire harness connector, do not disconnect. Check cavity (No.7 for passenger, No.8 for driver seat) for a range in voltage from approx. 1.72 – 3.0 volts. It should be within this range, If OK check the heated seat element. If NOT OK, check for the proper 5 volt supply to the heated seat sensor, from the module. Refer to Wiring for specific information. If 5 volts is not being supplied to the sensor from the module, replace the heated seat module.
4. Test the seat wire harness between the heated seat module connector and the heated seat wire harness connector for shorted or open circuits. If OK, refer to Diagnosis and Testing the Heated Seat Module in Electronic Control Modules, for the proper heated seat module diagnosis and testing procedures. If not OK, repair the shorted or open heated seat wire harness as required.
REMOVAL
1. For heated seat sensor replacement procedure (Refer to 8 - ELECTRICAL/HEATED SEATS/HEATED SEAT ELEMENT - REMOVAL).