Heated Seats Description and Operation. Chevrolet Evaluator 1985

For 1990-2009 cars

The driver and front passenger seats are heated using electric heater elements located in the seat cushions and seat backs. Battery voltage to the heater elements is controlled by the heated seat modules using inputs from the heated seat switches and the heated seat thermistors. Ignition voltage is supplied to the heated seat modules and to the heated seat switches. When the heated seat switch is in the low position, ignition voltage is supplied through the high/low switch signal circuit to the module. When the heated seat switch is in the high position voltage to the high/low switch signal circuit is reduced by the resistor within the heated seat switch, and high or low seat heater operation is determined by the voltage level of the high/low signal circuit to the heated seat module. The seat temperature is regulated by the module using an input from the thermistor located in the seat cushion. The thermistor is a temperature sensitive variable resistor and the module determines the seat cushion temperature by monitoring the signal voltage supplied to the thermistor. When the desired seat temperature has been reached the module will open and close the supply voltage to the heater elements as necessary in order to maintain the seat temperature.