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Why is a/c blowing out of defroster?

Discussion in 'Ford Trucks' started by Elite Property Services, Jul 18, 2010.

  1. Elite Property Services

    Elite Property Services Senior Member
    Messages: 230

    I have a 2003 F250 when I turn the a/c on it blows out of the defroster. Mechanic told me vacuum was fine and he wasnt sure what it could be. I still think its vacuum because sometimes when applying the brake it will switch to vents. Any ideas? Thanks Nathan
     
  2. drp

    drp Senior Member
    from ontario
    Messages: 170

    vacuum leak. Heating system defaults to defrost with a vacuum leak. Most common location 4wd auto hubs. Check if it will engage the hubs when set on auto.
     
  3. lotec25

    lotec25 Member
    from Florida
    Messages: 47

    is it just blowing out of the Defroster? or is it coming out of the regular vents? What does changing the controls do anything? Does heat still work?
     
  4. Elite Property Services

    Elite Property Services Senior Member
    Messages: 230

    I am still looking. It is blowing out of the defroster only no change when control switched to any position heat or a/c. Thanks Nathan
     
  5. lotec25

    lotec25 Member
    from Florida
    Messages: 47

    vacuum leak for sure then, check all the vacuum lines. The controller is all vacuum controlled, Weird that it will kick over when you apply brakes though.
     
  6. Elite Property Services

    Elite Property Services Senior Member
    Messages: 230

    It has only kicked over a few times when applying the brakes and when it did it shuttered like it was hesitating to switch. Is their any way to narrow the search down for the leak?

    Thanks Nathan
     
  7. lotec25

    lotec25 Member
    from Florida
    Messages: 47


    start here? does the hugs engage? if so, just a process of looking for worn out vacuum hoses. Not much i can think of but check the hoses man.
     
  8. Elite Property Services

    Elite Property Services Senior Member
    Messages: 230

    Yes i wll keep looking:dizzy:
     
  9. bluerage94

    bluerage94 Senior Member
    Messages: 398

    Do you have the electronic climate control?
     
  10. Elite Property Services

    Elite Property Services Senior Member
    Messages: 230

    No i don't. Don't those have an o-ring problem?
     
  11. Silverstreak

    Silverstreak Senior Member
    Messages: 168

    yeah vac leak, the conroller for the vent is right under the glove under the dash (or maybe you gotta take the glove door partway out..i forget) there is a vac-actuated valve that pulls the air deflector to the vent position, you can wire tie it halfway until you figure it out, or something might have disconnected the vacuum tube off the actuator
     
  12. TBElectric

    TBElectric Junior Member
    Messages: 5

    The vacuum line in the engine compartment which is white in color is either broken, sretched, or cut allowing a vacuum leak. It is located on the passenger side of the engine bay nearest the firewall. It usually runs behind the a/c dryer assembly. Hope this helps.