Abstract: A two-piece housing defines a cavity containing electric switch elements and a detent mechanism positioned for optimum characteristics. Axially spaced apertures in the housing support a manually controlled shaft for rotation. The shaft is drivingly coupled to the movable switch elements and the detent mechanism. A floating valve assembly, operated by the shaft and aligned by the shaft, is mounted on the outside of the housing on projections which flexibly support a valve stator containing vacuum ports. A rotor holds a selector plate against the stator for interconnecting ports. The rotor is keyed to the shaft for rotation and is spring biased toward the stator.