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Vacuum Motor Test

  1. With engine not running, air cleaner may be removed for this test. Disconnect vacuum hose from vacuum motor.
  2. Connect an external vacuum pump to vacuum motor. Apply specified vacuum for Door Fully Closed, see Door Fully Closed Less Than In. Hg in Air Control Door Opening Vacuum specifications table.
  3. Air control door should remain closed to outside air (open to heated air from shroud around exhaust manifold).
  4. Next, apply specified vacuum for Door Fully Open In. Hg, see Air Control Door Opening Vacuum specifications table. Air control door should open to outside air (closed to heated air).
  5. Apply 20 in. Hg to vacuum motor and pinch off hose. Vacuum should not leak down more than 10 in. Hg in 5 minutes. If vacuum motor fails any of these checks, replace it.
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