Operation

OPERATION

When a 2nd row heated seat switch is depressed a resistance (ohms) signal is sent to the Heated Seat Module (HSM), the module energizes the proper indicator Light Emitting Diode (LED) (low or high) in the heated seat switch by grounding the indicator lamp circuit to indicate that the heated seat system is operating. At the same time, the HSM energizes the selected heated seat sensor circuit and the sensor provides the module with an input indicating the surface temperature of the seat cushion.

The low heat set point is about 35° C (95° F), and the high heat set point is about 40° C (104° F). If the heated seat sensor temperature input is below the temperature set point for the selected temperature setting, the HSM energizes an N-channel Field Effect Transistor (N-FET) within the module which energizes the heated seat elements in the selected seat cushion and back. When the sensor input to the HSM indicates the correct temperature set point has been achieved, the module de-energizes the N-FET which de-energizes the heated seat elements. The HSM will continue to cycle the N-FET as needed to maintain the selected temperature set point. The 2nd row HSM operates on fused battery current received from the integrated power module.

If the HSM detects a heated seat sensor value input that is out of range or a shorted or open heated seat element circuit, it will indicate this condition by flashing the high and/or low indicator lamps in the affected heated seat switch. Testing and Inspection, for flashing LED diagnosis and testing procedures.