Heater and A/C controls

Discussion in '6.9L IH & 7.3L IDI Diesels' started by Alaskaman, Jul 14, 2018.

  1. Alaskaman

    Alaskaman Registered User

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    One small issue, I have no idea where to start.

    The heat and A/C both work, but the floor, vent and defrost position do not change. I can hear the blower motor working, but just a little air coming out . . . everywhere.

    Any input would be welcome. As a note, I did replace my Vacuum Pump thinking that would correct the problem along with my brakes. The Brakes work as advertised now, the selector control, no change.

    Thank you for your assistance.
     
  2. Vern

    Vern Registered User

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    I think you're right the selector business runs on vacuum. I had my f250 dash off the other day and saw that one of the servos that closes a door had the arm break off where it attaches to the door. That may have accounted for how much dust lined the whole interior. mind you I could still direct the flow of air. Good luck I hope at least to be encouraging!
     
  3. gnathv

    gnathv Full Access Member

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    Normally it is the vacuum line above the accumulator tank on passenger side. Connects to vacuum motor that’s on top almost under lip of fender right at firewall. The line is nylon and the heat makes it brittle.
     
  4. snicklas

    snicklas 6.0 and Loving It!! Staff Member

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    If it's coming out of all 3 sets of vents at the same time, it's more than likely, the blend door is stuck/damaged/broken. With no vacuum, it should all be coming from the defroster vents. No vacuum is a fail-safe of defroster, so you can keep the windshield clear.

    Look under the dash on the passenger side, where the heater core is, and check your doors. I bet your blend door is stuck, with something that has fallen down the defroster vent, or has come off the mount.....
     
  5. Alaskaman

    Alaskaman Registered User

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    Thanks for all the information. I'll get a chance to check it out in a few days.

    I'll send feedback then.
     
  6. Alaskaman

    Alaskaman Registered User

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    I haven't forgotten to report back. I have been swamped with company and was out of state visiting my new Great Grandson.

    Hopefully I'll report back this coming week. Thank you.
     
  7. riphip

    riphip Supporting Member Supporting Member

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    What year is your truck? Someone may be able to give you a part #
     
  8. Alaskaman

    Alaskaman Registered User

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    It is a 1993 F250. However, I haven't even had the time to troubleshoot the problem yet. Hopefully this coming week.

    Thank you.
     
  9. Alaskaman

    Alaskaman Registered User

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    Well, after checking all the Vacuum servos and vacuum lines, I finally dug into the dreaded heater box!

    I found the problem after pulling the Fan out . . . some type of critter (not a mouse or Rat) made a really nice nest inside the Fan rotor, and A/C box. After vacuuming and blowing out the Fan wheel, everything works great!

    Problem solved!

    Thanks to all who have given me input and suggestions.
     

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