[12v+]-----[switch]-------[solenoid]------[ground]
The dash switch
It uses the throttle opener which is originally part of the A/C circuit. When vacuum flows through this device, the arm is pulled upwards, which pulls on a lever on the throttle shaft to open the throttle, raising the idle speed. The solenoid simply controls when vacuum can flow through it, having one vacuum hose sourced from manifold vacuum and the other leading to the throttle opener.
Adjusting the idle speed is done in one of two ways, depending on which model of throttle opener you receive. One has a nut on the lower arm which can be screwed in or out to adjust the idle speed (see photo above). The other has a pin on top which is screwed in or out to adjust idle speed.
