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Defroster Vent

Discussion in 'The Garage' started by Tannerman, Jan 30, 2006.

  1. Tannerman

    Tannerman Registered Member

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    Hoping someone can help me with this one. I am having a bit of trouble with my heater system. I have good heat but can't get heat to upper defrost. I took apart the lower venting and the door to direct heat up does not open. I can manually open it but it will not on its own. I see that it is operated by a vacuum system but I can't seem to find any trouble with the lines(holes).
    I am thinking maybe a line is off that controls the heater diaphram or the unit is dead. The lines that go to the control levers all seem to be there and functioning. Where does the line to the diaphram go to to get the vacuum? I can't seem to find it without taking the whole darn thing apart. Or, do I need a new one?
     
  2. AV8

    AV8 Registered Member

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    Mine did the same thing. Turned out to be a disconnected vacuum line under the hood on the pass side IIRC.
     
  3. opfor2

    opfor2 1/2 ton status

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    Ya someone shed some light on this problem. seems like a lot of us have this problem. My 90 will blow heat from the dash vents and heater vents or in defrost it will blow from the dash and defrost vents.
     
  4. Tannerman

    Tannerman Registered Member

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    Thanks for the replies guys. AV8, I'm not sure what the IIRC is. If possible please let me know. I'm going to look for a disconnected line for the heater diaphram into the engine compartment. If anyone has a diagram of the vacuum lines this would be greatly appreciated so it would seem. If I can't find a line through the firewall I'm going to run a line from the intake manifold to see if it works when its open. I presume if it does I'll have to tee it off. I'll post results here if it helps anyone else.
     
  5. grtwhite

    grtwhite 1/2 ton status

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    IIRC = If I Remember Correctly
     
  6. Tannerman

    Tannerman Registered Member

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    I was thinking about this. Are we talking about the
    VRC=Vacuum Recovery Can?
     
  7. kd7kmp

    kd7kmp Registered Member

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    I had this problem a few months ago. There was a broken vacuum line under the hood near the distributor. Double and triple check ALL vacuum lines under the hood. If one is leaking or broken it will cause the problem you are experiencing.

    Kevin
     
  8. 86haubs

    86haubs 1/2 ton status

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    What is the year and factory setup (eng/trans) your truck came with? I have the vaccum diagrams for a 1980 and up.;)
     
  9. Tannerman

    Tannerman Registered Member

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    86haubs, the truck is a 1989 350 with a 700 tranny. If you have the vacuum diagram it would be greatly appreciated.
     
  10. George_Pimpdaddy

    George_Pimpdaddy 1/2 ton status

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    i would also like to get that vacum diagram too if possible as i have the same blazer year.
     
  11. 86haubs

    86haubs 1/2 ton status

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    Okay when I get home tonight I will post them. All they are is the diagrams from my Chiltons book. Expect to see them around 6:30pm PST.
     
  12. 86haubs

    86haubs 1/2 ton status

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    Okay, so I get home and look in my book and the diagrams only go up to '86. I don't know if it is shat you guys are looking for but I went ahead and scanned them to my Webshots, here is the link: http://community.webshots.com/user/indy500ss

    **Warning, these photos are about 2megs each, I had to make them that large so you can read the writing.**

    Let me know if this helps, hope it does. Let me know the fix also, I have a buddy with the same problem.
     
  13. 86haubs

    86haubs 1/2 ton status

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    So what is the verdict? Did the diagrams help at all? If so what was the fix.
     

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