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Electrical Vacuum Control Valve

  1. Electrical vacuum control valve may be either open or closed at room temperature, but should reverse the position when engine is at full operating temperature. While engine is cold, measure continuity across switch terminals. See Fig 1. Note if switch is open or closed.
    Fig 1: Identifying Electrical Vacuum Control Valve Ports
    G90C14334Courtesy of FORD MOTOR CO.
  2. Warm engine to normal operating temperature. Measure continuity across switch terminals again. Continuity should be opposite of cold condition. If switch continuity does not switch, replace valve. Check vacuum function of valve as described in VACUUM CONTROL VALVE.