Theory Of Operation-MULTIFUNCTION Switches

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 multifunction switches of the SCM use resistor multiplexing to control the many functions and features it provides using a minimal number of hardwired circuits. The switches provide resistor multiplexed outputs to the SCM, indicating the selected switch positions. The SCM then sends these activation requests over the CAN-C data bus to the BCM and other electronic modules in the vehicle. THE SCM is integral to the clockspring.

Left Multi-Function Switch- is used to select the turn signal lamps (right or left) and to select the headlamp beam (low, high or optical horn).

Right Multi-Function Switch- provides the vehicle operator with a control interface for the following wiper and washer system functions: Continuous Wipers, Intermittent Wipers, Wiper Mist Mode, and Washer Mode

In addition, a small TRIP push button at the very end of the right multifunction switch control knob provides a signal to the Instrument Panel Cluster (IPC) that will reset the currently displayed trip odometer A or B value to zero.

The right and left multi-function switches for this vehicle is integral to the clockspring and stalk unit. If any function of the switch is ineffective, or if the switch is damaged, the entire clockspring and stalk unit must be replaced