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Heater/AC Air Flow Control Problem

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Old Sep 7, 2023 | 08:05 PM
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Default Heater/AC Air Flow Control Problem

Having a problem getting the air flow to change when moving the controller. Air stays coming out of the bottom only. No air from ac vents or defrost.
Any help would be appreciated.
Pat

Every working fine now. Had a vacuum leak

Last edited by pats67copo; Sep 23, 2023 at 06:49 PM.
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Old Sep 7, 2023 | 08:09 PM
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Originally Posted by pats67copo
Having a problem getting the air flow to change when moving the controller. Air stays coming out of the bottom only. No air from ac vents or defrost.
Any help would be appreciated.
Pat
https://www.corvetteforum.com/forums...-switch-2.html
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Old Sep 8, 2023 | 05:01 AM
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Hi,
Thanks for your response. I was told the relay is behind the glove box. Is that correct and where is this piece your showing located?
Pat
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Old Sep 8, 2023 | 07:59 AM
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Here is a drawing showing the vacuum system. It is for a '69, but that system is pretty much the same for a few years.

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Old Sep 8, 2023 | 08:44 AM
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Ah didn’t notice you had early one..
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Old Sep 8, 2023 | 09:21 AM
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Originally Posted by pats67copo
Having a problem getting the air flow to change when moving the controller. Air stays coming out of the bottom only.
First thing I'd do is make sure your HVAC controls actually have any vacuum to work with --- that the path from the manifold to the controls is OK.

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Old Sep 8, 2023 | 09:33 AM
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Originally Posted by wadenelson
First thing I'd do is make sure your HVAC controls actually have any vacuum to work with --- that the path from the manifold to the controls is OK.
Thanks I will check that out
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Old Sep 8, 2023 | 09:34 AM
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[QUOTE=robertea;1607023015]Here is a drawing showing the vacuum system. It is for a '69, but that system is pretty much the same for a few years.
[/QUOTE
78 has a different controller
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Old Sep 8, 2023 | 09:46 AM
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So what year is your car?
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Old Sep 8, 2023 | 09:54 AM
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[QUOTE=pats67copo;1607023272]
Originally Posted by robertea
Here is a drawing showing the vacuum system. It is for a '69, but that system is pretty much the same for a few years.
[/QUOTE
78 has a different controller
it’s a 78 with AC
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Old Sep 8, 2023 | 10:21 AM
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Then see post 2..link
behind the glove box is only hot water shutoff



Last edited by interpon; Sep 8, 2023 at 10:28 AM.
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Old Sep 8, 2023 | 01:58 PM
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Your profile doesn't show you having a '78. It lists '64, '71 and 2007. I was guessing you were referring to the '71.
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Old Sep 8, 2023 | 05:18 PM
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I have a non ac version of the gizmo in the red box above on my workbench right now, if it'd help you out. Not sure.
can add pics later if you think it might.


looking at it, I think it's the same, two hoses on it
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Old Sep 10, 2023 | 12:26 PM
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Old Sep 10, 2023 | 04:15 PM
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Originally Posted by Dodosmike
Yes, that actuator is for a NON A/C car, push/pull to move door and requires 2 vacuum lines.
A/C actuator is a single line.
If OP has some vacuum grease the witch hat rubber seal can be rolled back, apply some v-grease to shaft ans inside of seal.
Sometimes it works...
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Old Sep 10, 2023 | 04:24 PM
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The same vacuum function switch was used on both A/C and NON A/C cars.
Difference is the ports of the switch and what they control.
A/C & NON A/C porting...

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