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 current to the heating element.

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