Calais FWD L4-151 2.5L (1985)
Thermostatic Air Cleaner Vacuum Switch: Description and Operation
Thermac Secondary Vacuum Break Thermal Vacuum Switch (SVB-TVS)
This switch acts as a vacuum connection for the thermac air cleaner control and a thermal control for the secondary vacuum break diaphragm. Ports 1
and 2 of this switch are always connected and port 3 is sealed when cold and connected to the other ports when warm.