Blend Door for dummies?

Discussion in 'Tech Discussion' started by Evil Bob, Dec 5, 2018.

  1. Evil Bob

    Evil Bob Full Access Member

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    1988 K5 Factory a/c truck (a/c deleted by previous owner)- a buddy helped me out and relpaced my heater core (thank god for mechanic buddies). Only thing is now my vents are all screwed up. Heat pretty much come out the vents and floor only no matter what setting I have it on. My defroster barely works at all which is no bueno. I am guessing it’s my blend door ‍♂️ Is there a go to you tube video for this or a good schematic? I am too embarrassed to keep asking my buddy to help out even though it may have been something he did or didn’t do when reinstalling the heater core.

    All suggestions are greatly appreciated thanks.
     
  2. WFO

    WFO Full Access Member

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    Check to see if your vacuum line that comes out through the firewall on the passenger side is hooked up.
     
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  3. Evil Bob

    Evil Bob Full Access Member

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    Yep I did and it’s all good. Outside of that I am clueless with this stuff lol
     
  4. Snoots

    Snoots Supporting Member Supporting Member

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    HVAC.JPG HVAC 2.JPG HVAC 3.JPG
     
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  5. PrairieDrifter

    PrairieDrifter Full Access Member

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    The blend door just controls temp. I believe there are 3 maybe 4 vacuum actuators that control the vent doors separately. Those need the vacuum lines to be hooked up from the control unit to each actuator.

    It would have been a good idea to lube all the doors when the heater box was out. Not sure if you guys did that or not.
     
  6. Evil Bob

    Evil Bob Full Access Member

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  7. Evil Bob

    Evil Bob Full Access Member

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    I doubt it but I will be tearing it apart next and will be sure to do it. thanks...
     
  8. chengny

    chengny Full Access Member

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    Make sure the diverter door connecting link is intact and secured to the door (and actuating arm):

    HPIM1580.jpg
     
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  9. Rusty Nail

    Rusty Nail Build the wall - deport them all!

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  10. Snoots

    Snoots Supporting Member Supporting Member

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    X2!

    Those plastic things are VERY BRITTLE!!!

    Be very careful with them and use some PB Blaster on them. Also, if it's very cold I wouldn't mess with them unless I had a small electric heater or heat gun just to warm them up (not direct high heat).

    Don't ask how I know this.

    I used to have a diagram that showed the workings of the vacuum actuator/selector switch but can't find it.

    Start out with what WFO recommended tho.
     
  11. Snoots

    Snoots Supporting Member Supporting Member

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    Try these . . .

    57433492.JPG 57433537.JPG
     
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  12. Evil Bob

    Evil Bob Full Access Member

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    thanks for all the help... My buddy broke a bunch of sh!t when he took the dash out :(
     

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