Theory Of Operation

To control the temperature of the Heated Steering Wheel (HSW), the Comfort Seat and Wheel Module (CSWM) provides power and return circuits to the HSW using a Pulse Width Modulation (PWM) signal to control the current to the heating element.

To monitor the temperature of the heating element the HSW uses an internal embedded Negative Temperature Coefficient (NTC) type thermistor which is connected to the Steering Wheel Switch (SWS). The SWS sends the temperature value over a LIN bus circuit to the Steering Column Control Module (SCCM). The SCCM sends the temperature value to the CSWM over the CAN-IHS data bus.