Distributor Thermal Vacuum Switch (EGR-EMR-DTVS)

When engine coolant temperature is below the switching point, this switch receives manifold vacuum from port 2, which is directed through the TVS from port 1. Port 3 is vented through port 6 while ported vacuum at port 4 and distributor ports are sealed.
When engine coolant temperature is above the switching point, the distributor port 5 receives manifold vacuum from port 1. Port 2 is now vented through port 6, while port 3 receives ported vacuum from port 4.