The wiper thing is the TPS, Throttle Position Sensor. It serves to tell the PTCM what the current state of the butterfly valve opening is so it can then decide to add or subtract throttle depending upon it's current mood.
The PTCM looks at throttle pedal position, intercooler temperature, RPM and the current alignment of Earth and Mars and a slew of other things to decide if it wants to engage the supercharger.