Circuit/System Description
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The driver and front passenger heated seats are controlled by separate heated seat switches that are located on the HVAC panel. When a heated seat switch is pressed, a serial data message is sent from the HVAC control module to the memory seat module (MSM) indicating the heated seat request. In response to this message, the MSM applies battery positive voltage through the element supply voltage circuit to the appropriate seat heating elements. The module controls the seat temperature by providing a PWM ground through the heated seat element control circuits to the seat heater elements. The MSM then sends a serial data message back to the HVAC control module to either illuminate or turn off the appropriate temperature indicators.