Power Seat Control Module: Description and Operation
HEATED SEAT MODULEHeated Seat Module:
Two heated seat modules are used on this vehicle, one for each front seat. The heated seat modules are located under each front seat cushion frame. The heated seat module has a single connector receptacle that allows the module to be connected to all of the required inputs and outputs through the body wire harness.
The heated seat module is an electronic microprocessor controlled device designed and programmed to use inputs from the ignition switch, the heated seat switch and the heated seat sensor to operate/control the heated seat elements in each front seat.
The heated seat module cannot be repaired. If the heated seat module is damaged or faulty, the entire module must be replaced.
The heated seat module operates on fused battery current received from the ignition switch. The module is grounded at all times through the body harness. Inputs to the module include a resistor multiplexed heated seat switch request circuit for each of the two heated seat switches 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 and sensors.
When a heated seat switch (Driver or Passenger) request signal is received by the heated seat module, the 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 38° C (100.4° F), and the High heat set point is about 42° C (107.6° 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.