Circuit/System Description

The driver and passenger seat heating elements are controlled by a common high current relay internal to the heated seat module (HSM) and by individual low side element control circuits. The HSM connects the heater element supply voltage circuits for both seats to a common reference point. This reference point is biased to approximately 2.0 volts. Before the HSM will allow heated seat operation, it checks to see if the heating element supply voltage circuits and control circuits are shorted to ground or voltage. Once the HSM verifies that it is not closing to a shorted heating element, it allows for heated seat operation. The HSM will then continue to monitor the heating elements for a shorted circuit.