Component Functional Description-Multiplex (MUX) Switch
Component Functional Operation: The Speed Control (S/C) Switch is a Multiplex (MUX) Analog Switch. The S/C Switch has one MUX signal and a sensor ground circuit that are hard-wired to the Body Control Module (BCM). The signal circuit is typically a 5.0 volt pull up signal. The S/C Switch is open when the system is switched off. The input signal should be 5.0 volts to the BCM when switched off. Once the S/C Switch is turned on, it functions as a single MUX signal. Aside from the On/Off portion of the switch, the other switch positions are momentary switches. They are capable of reporting multiple switch position inputs using one signal and sensor ground circuit. Each switch position has a unique resistor that varies the voltage of the signal circuit for each position selected (I.E. up/down, left/right, open/close, etc.). The resistors can be configured in series or parallel inside the MUX Switch.
The generic graphic below depicts the functionality of the S/C Switch.