72 skylark AC works but not thru vents

Discussion in 'The Big Chill' started by corkgs, Aug 22, 2022.

  1. corkgs

    corkgs Well-Known Member

    The ac works through the lower vents(heater mode) I can reach 1 of the vacuum door controller under the dash but I think I need to get to another 1
    Any ideas?
     
    Dano likes this.
  2. PCUB

    PCUB PCUB

    Check behind the RH front kick panel under the AC outlet/glove box; my 71 has a vac motor connected to the fresh air intake flap that controls flow to the upper AC ducts (mine was disconnected from the vac line) and also not working with a hand-held vac tester. Repro vac motors were available (if needed) a couple years ago.... Hopefully it is still the case. I believe the service manual has a vac line/component layout schematic so you can see how the system is connected to the control panel and to the vacuum storage tank in the engine bay.
     
    Last edited: Aug 22, 2022
  3. corkgs

    corkgs Well-Known Member

    I will check thanks
     
  4. GSX 554

    GSX 554 Gold Level Contributor

    Cork . Be sure the vacuum lines are both attached to the Storage tank that looks like a large softball under the hood . When the AC comes out on the floor instead of the dash its the " DEFAULT " for no vacuum .
     
    corkgs likes this.
  5. corkgs

    corkgs Well-Known Member

    I can make it work unhooked green and orange vac lines at the actuator connect them together everything works except recirc door (vac not attached )
    hook the green up to the actuator the door opens for cabin air as long as you hold your finger over the orange line. Why did Buick need to run 1 constant vacuum at this actuator (and it somehow creates a vac leak) when I saw other gm with only 1 vac port for the same door?
    at this time I will cap the orange line and connect the green to the door until I find a replacement
     
  6. corkgs

    corkgs Well-Known Member

    which store has the vacuum actuators
     
  7. Redmanf1

    Redmanf1 Gold Level Contributor

    It could be your vacuum control mix switch.
     
  8. corkgs

    corkgs Well-Known Member

    I had a used 1 that was good and the vacuum was the same any way we tested. the door doesn't open with the vacuum at the recirc (may not have strong enough vacuum) as long as I cap off the orange line the system works all functions except the recirc door
     
  9. GSX 554

    GSX 554 Gold Level Contributor

    Cork I am not sure about the " A BODY " cars but the larger cars like Electra's recircuitation door had a spring to pull the door shut and the vacuum pulled it open if I remember correctly . Used to be able to see the spring end where it attached from under the hood .
     
  10. corkgs

    corkgs Well-Known Member

    yes it has a spring on the inside attached to the actuator
     

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