Edmunds Answers



  • ace42007 04/27/10 10:03 pm PST

    check all adjustments on all three different panels make sure all set to red and rear if want heat throughout and all settings in main adjustments

  • wwest 03/18/12 3:03 pm PST

    My 1994 Ford Aerostar uses engine vacuum for servomotor control of the various HVAC functions. It has a vacuum reservoir and a one way valve (think diode) between the reservoir and the engine manifold vacuum source.

    On my '94 with that "diode" having failed the HVAC control system vacuum will decline under acceleration and the system outlet outflow will then switch, of itself, into windsheld defrost/defog/demist...HOT airflow to the interior windshield surface.

    I don't know if Ford still uses engine vacuum for HVAC servomotor "drive" source but it's worth checking your engine vacuum reservoir storage system if so.


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