AC and heater system

Discussion in 'Troubleshooting & Diagnosis' started by Andy Jones, Jan 5, 2021.

  1. Andy Jones

    Andy Jones Veteran Member

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    Hi all
    Am replacing the heater and ac cores to try and make the heater work in the 79 camaro.
    I have a couple of questions.
    1. When taking the ac box out, I came across a vacuum pipe in the engine bay connected to nothing (see picture). Any idea where it goes?
    2. I count 3 vacuum valves that I can see. The diagrams show 4 or 5. Am I missing something? Is one inside the heater box?
    3. Is there a cheap aftermarket ac/heater system that would be better to install?
    Any help is always appreciated
    Thanks
    Andy
     

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  2. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

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    1. There's only one little vacuum line like that in the engine compartment of a 79.
    It connects to the vacuum reservoir "ball" on one end and the other end feeds through the firewall and supplies vacuum to the control head.
    The other connection on the vacuum ball goes to your intake manifold.
    upload_2021-1-5_18-20-6.png

    2. I believe there's a total of 4 vacuum actuators...
    1 in the passenger side kick panel.
    1 operates the cowl flap and it's down inside the cowl panel. (Closes cowl flap for "Max" air.)

    1 on the driver's end of the under-dash box. (Operates the defroster flap in the box.)

    1 on the firewall side of the box. (This one self centers and two vacuum lines connect to it to move it either direction.)

    Check the pink vacuum line which goes into a little rubber flap on the box near the hot/cold cable connection. It's probably brittle and cracked.

    [​IMG]

    3. "Cheap" aftermarket A/C... No such thing for these cars. :(
    Vintage Air and a couple of other companies make aftermarket systems but they require some re-engineering and they aren't cheap.
     
  3. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

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    upload_2021-1-5_20-33-38.png

    Basic vacuum line diagram.
    Line colors may be different but this is the way they are connected on my 80.
     
  4. Andy Jones

    Andy Jones Veteran Member

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    That is awesome. Thank you
     
  5. Andy Jones

    Andy Jones Veteran Member

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    Hi all
    So I can only find 3 vacuum actuators. 2 on the heater box and 1 on the pax kick panel. Where in the cowl is the 4th one?
    Also cannot find the accumulater ball or where it would connect.
    Also below is my heater switch connections and where I could get new tubes.
     

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  6. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

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    It's under the flap on the passenger side of the cowl.
    You can see the flap if you look down through the cowl screen.
    You can't see this vacuum actuator unless you unbolt the flap inside the cowl.

    upload_2021-1-10_16-48-4.png
    There's a vacuum line which runs to it (from a "T" connection) through a grommet behind and above the glove box door latch.
    The other side of the "T" runs to the passenger kick panel vacuum actuator.

    The vacuum ball is either bolted to the firewall or to the A/C evaporator case in the engine compartment.
    The small line from it runs through a grommet on the firewall a couple of inches from the distributor. (Between the distributor and the A/C evaporator case.)
    The larger connection on the vacuum reservoir goes to the intake manifold.

    If you can't find it... It's probably missing.

    Sorry... I don't know where to get new vacuum lines for this system.
    It looks like you have all 5 of them in place.

    Unless they are broken, they probably aren't a problem.
    Your main issue is most likely a lack of vacuum supplied by the engine (through the missing reservoir ball).
     
  7. Andy Jones

    Andy Jones Veteran Member

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    Ah. Got it. Can't see the valve but did find the pipe.
    The pipe to the 2 way actuator valve is cracked and broken. Will replace that.
    Can't find the reservoir so it's probably long gone. Will try and find another.
    Thanks
     
  8. DougD

    DougD New Member

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    The ball is readily available from Dorman and other aftermarket companies, if you aren't after the perfect original for a resto.
     
  9. Andy Jones

    Andy Jones Veteran Member

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    Thanks. Not worried about perfect. Just working :)
     

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