Air Control Valve

Remove air cleaner. Disconnect vacuum hose from air control valve and connect a vacuum pump to nipple. Apply 19.8 in. Hg of vacuum. Vacuum should hold. At 2.6 in. Hg of vacuum or less, valve should be in down (cold air only) position. At 7.4 in. Hg of vacuum or more, valve should be in up (hot air only) position.