Theory Of Operation

The Heated Seat Module (HSM) controls the Heated Steering Wheel (HSW) heating element temperature by using a Pulse Width Modulation (PWM) of the current to the element. The HSM uses a high side driver to adjust the PWM duty cycle to maintain a desired temperature. The wiring to the HSW heating element is routed from the HSM through the Steering Column Control Module (SCCM) and Clockspring.

The HSW temperature is monitored by a temperature sensor embedded in the steering wheel. The HSW temperature sensor is wired to the Heated Steering Wheel Switch. The Heated Steering Wheel Switch sends the temperature value over a Local Interface Network (LIN) Bus to the SCCM. The SCCM then sends the temperature value to the HSM over the Controller Area Network (CAN) Bus.