Heated Seat Module: Operation

The heated seat module operates on fused battery current received from the integrated power module. The module is grounded at all times through the seat wire harness. Inputs to the module include a resistor multiplexed heated seat switch request circuit for the heated seat switch and the heated seat sensor inputs from the seat cushions of each front seat. In response to those inputs the heated seat module controls battery current feeds to the heated seat elements.

When a heated seat switch request signal is received by the heated seat module and the enable input is high, the heated seat module energizes the selected heated seat sensor circuit and the sensor provides the module with an input indicating the surface temperature of the selected 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 seat cushion surface temperature input is below the temperature set point for the selected temperature setting, the heated seat module 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 module indicates the correct temperature set point has been achieved, the module de-energizes the N-FET which de-energizes the heated seat elements. The heated seat module will continue to cycle the N-FET as needed to maintain the selected temperature set point.