Theory Of Operation

WARNING: This page is about a different car, the 2024 RAM ProMaster EV. However, it is still accessible from the selected car via links, so may be relevant.

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 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 Body Control Module (BCM) through the Clockspring. The BCM then sends the temperature value to the HSM over the Controller Area Network (CAN) Bus.