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Vacuum Switch A

  1. Remove connector from control unit and remove vacuum hose from vacuum switch A. Using an ohmmeter, measure continuity between Black/Yellow and Brown/White wire terminals on connector. There should be continuity.
  2. Connect vacuum pump and gauge to vacuum port on vacuum switch A. Slowly draw vacuum and watch ohmmeter scale. When vacuum increases above 3.9 in. Hg, switch opens and ohmmeter should show no continuity (infinite resistance). Replace vacuum switch A if it does not operate as outlined.