Results 1 to 10 of 10

Thread: Heat Defrost Air Con Vacuum Lines

  1. #1
    Aspen and Volare Senior Member SpeedBanana1977's Avatar
    Join Date
    Dec 2015
    Location
    Chicagoland
    Country:
    United States
    Posts
    106
    Thanks
    30
    Thanked 10 Times in 8 Posts

    Heat Defrost Air Con Vacuum Lines

    I recently fixed a problem with my heater control box and its vacuum hoses. Basically, I was getting only heat--no defrost and no vent--and no way to turn the heat up or down. Turns out that there were multiple issues: 1) heater control cable had been cut off by some previous owner and 2) vacuum lines to the heater box were falling out all over.

    The control cable was an easy fix; just a matter of finding one with the right connections (which are red "flags"). I could have probably created one with another cable. One thing to note is that non-a/c cars have both vent (yellow) and heat (red) cables; a/c cars have only the red heat cable.

    The vacuum lines proved roved more challenging because 1) there's no way to tell which one goes where and 2) the hard plastic lines kept falling out before I could get them connected. On the first point, thanks to user 77SuperPak for the vacuum diagram. On the second, I found that many newer Chryslers have similar heater controls that use silicone vacuum lines, so I headed out to the junkyard and pulled a few off some PT Cruisers and an old Jeep. Turns out that the silicone lines fit into the F-body vacuum connectors tightly after a little convincing--which is good in this case as it produces an airtight fit. Silicone tubes are probably available elsewhere but the auto parts store by me had no clue what I was after. Plus, I always get new ideas at the junkyard!

    Just thought I'd share this in case it helps anyone else. I will attach pictures in a separate post.
    Last edited by SpeedBanana1977; 03-08-2016 at 02:24 PM.

  2. The Following User Says Thank You to SpeedBanana1977 For This Useful Post:

    77superpak (03-08-2016)

  3. #2
    Aspen and Volare Senior Member SpeedBanana1977's Avatar
    Join Date
    Dec 2015
    Location
    Chicagoland
    Country:
    United States
    Posts
    106
    Thanks
    30
    Thanked 10 Times in 8 Posts
    Click image for larger version. 

Name:	AC Vent.jpg 
Views:	48 
Size:	98.7 KB 
ID:	2216

  4. #3
    Aspen and Volare Senior Member SpeedBanana1977's Avatar
    Join Date
    Dec 2015
    Location
    Chicagoland
    Country:
    United States
    Posts
    106
    Thanks
    30
    Thanked 10 Times in 8 Posts
    "Before" picture of the connector with the old, harder plastic lines and not necessarily in the right place. Note that the silicone lines fit into both sides, so the factory male connector (white clip pictured here) isn't really necessary.
    Click image for larger version. 

Name:	Vacuum.jpg 
Views:	47 
Size:	97.6 KB 
ID:	2217

  5. #4
    Aspen and Volare Senior Member Rory's Avatar
    Join Date
    Oct 2015
    Country:
    Great Britain
    Posts
    168
    Thanks
    29
    Thanked 18 Times in 13 Posts
    This sounds useful. Same problem here: no way of regulating or directing the flow of air, just a constant hot breeze which is particularly unpleasant during the summer. Especially since the a/c doesn't work (I'll remove it while swapping the engine). Not sure I understand the diagram though and where these cables/tubes live. I suppose you have to remove the dash?

  6. #5
    Aspen and Volare Senior Member SpeedBanana1977's Avatar
    Join Date
    Dec 2015
    Location
    Chicagoland
    Country:
    United States
    Posts
    106
    Thanks
    30
    Thanked 10 Times in 8 Posts
    Hey Rory. The cable runs from the heater control box to behind the glove box, so to get at the passenger side end, the glove box and all have to come off--which requires that the dash pad and the passenger side kick panel come off.

    The vacuum line comes through the firewall right above the gas pedal. I think it's easier to get at if you take off the panel below the steering wheel. The lines run up to the heater control box and to the various actuators. Mine had an extension of about a foot on the control box end-- which is the part I replicated in silicon.

    Hope that helps; I'm relatively new at this so others might have more info/corrections.

  7. The Following User Says Thank You to SpeedBanana1977 For This Useful Post:

    Rory (03-08-2016)

  8. #6
    Aspen and Volare Senior Member Rory's Avatar
    Join Date
    Oct 2015
    Country:
    Great Britain
    Posts
    168
    Thanks
    29
    Thanked 18 Times in 13 Posts
    Cool! I'll look into this after completing a few more jobs on my ever growing list (*sigh*).
    I may replace the entire dash at some point, that's probably a good opportunity to check the heater controls.

  9. #7
    Aspen and Volare Super Member doublechaz's Avatar
    Join Date
    Oct 2015
    Location
    AZ
    Country:
    United States
    Posts
    932
    Thanks
    65
    Thanked 80 Times in 71 Posts
    Is the check valve from the diagram in the engine bay or under the dash? Some of my climate controls were missing when I got mine and I pieced it together, but I don't remember anything like that check valve so I don't have one unless it's hidden under the dash.

  10. #8
    Aspen and Volare Senior Member SpeedBanana1977's Avatar
    Join Date
    Dec 2015
    Location
    Chicagoland
    Country:
    United States
    Posts
    106
    Thanks
    30
    Thanked 10 Times in 8 Posts
    Doublechaz--I found the check valve to be under the dash but lower--closer to where the vacuum line comes through the firewall. It's the round white thing to the left of the silver actuator. (note: don't follow the color scheme in the picture--I had to use black tubes for more than one of the connections). Hope that helps.
    Click image for larger version. 

Name:	Vacuum Connections.jpg 
Views:	27 
Size:	77.6 KB 
ID:	2233

  11. The Following User Says Thank You to SpeedBanana1977 For This Useful Post:

    Rory (03-11-2016)

  12. #9
    Aspen and Volare Super Member doublechaz's Avatar
    Join Date
    Oct 2015
    Location
    AZ
    Country:
    United States
    Posts
    932
    Thanks
    65
    Thanked 80 Times in 71 Posts
    I'll check for it, but the line from the controls to the tree on the manifold was missing on mine. I just don't remember if it was missing all the way from the controls, or from a check valve.

    Is the purpose of this valve to stop your climate controls from going crazy when you stomp on the gas and eliminate manifuld vacuum?

  13. #10
    Aspen and Volare Senior Member SpeedBanana1977's Avatar
    Join Date
    Dec 2015
    Location
    Chicagoland
    Country:
    United States
    Posts
    106
    Thanks
    30
    Thanked 10 Times in 8 Posts
    Not entirely sure, but a check valve usually ensures that something (like water or air) travels only in one direction. Maybe in this case, it ensures that only the necessary amount of vacuum gets through to the heater system?

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •