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Where to plug this vacuum line in

Discussion in '6.9L IH & 7.3L IDI Diesels' started by Suleiman Saadeh, Apr 28, 2019.

  1. Suleiman Saadeh

    Suleiman Saadeh Full Access Member

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    It's from the harness that connects in the heater box. I had an engine fire that melted the lines but I have no idea where the black goes. I'd greatly appreciate being pointed in the right direction

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  2. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

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    It goes to one of the ports on the check valve behind the dryer
     
  3. Suleiman Saadeh

    Suleiman Saadeh Full Access Member

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    What do you mean by the dryer? I'm not sure what that is.
     
  4. Randy Bush

    Randy Bush Full Access Member

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    [​IMG]The dryer looks something like this.
     
  5. Suleiman Saadeh

    Suleiman Saadeh Full Access Member

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    I believe it may have been connected at the sensor looking plug with the TEE in front of it before but I'm not sure how the other lines hook together then. I do not see any other port aside from that one that could be connected to. I remember pulling the connector off at the sensor when everything got melted in the fire but I dont know how it all connecta.

    20190428_180201.jpg

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  6. Suleiman Saadeh

    Suleiman Saadeh Full Access Member

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    The heat an ac works fine but i cant get it to switch from defrost. I've looked up the causes and I just dont know if it's the vacuum line not being right or if the solenoid could be bad
     
  7. DaveBen

    DaveBen Supporting Member Supporting Member

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    If all you get is defrost, then you are not getting vacuum to the heater. This is a default when the vacuum goes out.
     
  8. Randy Bush

    Randy Bush Full Access Member

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    The black line coming out of the harness goes to the T fitting, think it is like a check valve. Vacuum goes to that line anyhow to make your defrost work correct I believe. This is a picture on my 90 f250

    20190428_173721[2183].jpg
     
  9. Randy Bush

    Randy Bush Full Access Member

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    In your first picture the line coming out of the bottom of that T going to the MAP senser can just run to you vacuum manifold on the firewall . And I do believe you can plug your black line that you don't know where goes there, the bottom of that T
     
  10. Suleiman Saadeh

    Suleiman Saadeh Full Access Member

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    Is there a possibility that this, solenoid I believe, could have got damaged in the engine fire? I got a vacuum gauge last night and I'm gonn see if my system is loosing vacuum but if not what would that thing be called?

    20190428_183017.jpg
     
  11. rsaltaresjr

    rsaltaresjr Registered User

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    That's the vacuum solenoid that operates the door for outside air versus recirculating air. The one that directs air between defrost, dash louvers and floor heat is under the dash in the center. You're definitely not getting vacuum to the hvac Controls.
     
  12. Randy Bush

    Randy Bush Full Access Member

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    Did you get the black line that you didn't know where goes hooked back up? It feeds vacuum to your dash controls then back to this vacuum switch. Put a vacuum pump or suck on that line will tell you if it is working or not.
     
  13. Suleiman Saadeh

    Suleiman Saadeh Full Access Member

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    Yeah I bought another hand pump with a gauge because I lost the one I bought last year. I connected it to the line coming from the vacuum pump and it only reads 5 inHg. I just replaced the vacuum pump a year ago I'm pretty sure but perhaps the fire damaged it because it was having this issue right after that and I always thought it was the lines not being connected
     
  14. Randy Bush

    Randy Bush Full Access Member

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    Well that is not good if you are checking right at the pump. Replace it and hook up that black line if you have not already and things should work right.
     
  15. Suleiman Saadeh

    Suleiman Saadeh Full Access Member

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    Yeah that's what I was thinking but then I connected the hose to the vacuum distributor and the other end to the pump and wasnt getting a vacuum. Checked each line with my finger against the each end one by one and found the brake booster to be leaking too. The booster was brand new a year and a half ago and didnt get no more than 10-15k miles at the most.

    I wonder if the fire could've damaged both even though the booster was on the opposite end of the engine bay or if I could've done something wrong during installation or if it was just a bad booster because my brakes havent been right since I changed the booster and master cylinder
     

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