Ported Vacuum Switches (PVS) are heat-sensitive devices that turn vacuum pressure on or off to vacuum related components such as EGR valves or distributor advance mechanisms. Can be found on intake manifold, water outlets or engine block. A damaged or malfunctioning PVS can affect engine performance such as horsepower, fuel efficiency and emissions.

Switches are identified by color, number of ports and OE number. Color of the PVS will be a solid color or painted on top. OE number will be stamped or embossed on the side.