3-Way Solenoid

This electro-vacuum valve has connections from intake manifold vacuum and to servo diaphragm. Solenoid portion is energized by electrical connections to engine speed switch (air conditioning relay on models so equipped) and ignition switch.

As engine speed switch senses engine RPM within operating range, it will open 3-way solenoid to allow passage of intake manifold vacuum which positions servo diaphragm. This causes throttle plate to open slightly.