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Old 07-24-2022   #1
CamP
 
Join Date: Jun 2012
Location: fort worth
Posts: 183
Default AC blows out floor and defrost vents?

My 1990 ZR-1 with C68 AC is not blowing air out of the dash air vents. It is blowing cold air out of the floor and defrost vents. Anyone else have this issue?
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Old 07-25-2022   #2
GOLDCYLON
 
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Default Re: AC blows out floor and defrost vents?

Quote:
Originally Posted by CamP View Post
My 1990 ZR-1 with C68 AC is not blowing air out of the dash air vents. It is blowing cold air out of the floor and defrost vents. Anyone else have this issue?
The problem is your HVAC controller located above the gas pedal and it is a bear to get to. You will need to source a replacement. At least it's not a ZR-1 only part. I remember somebody on the board here who was able to rebuild his but that was a long while ago.
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Old 07-25-2022   #3
DRM500RUBYZR-1
 
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Location: Mullica Hill, New Jersey
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Default Re: AC blows out floor and defrost vents?

That is the default mode when failed, so that you can see in the cold or wet when defrost or defog is required.

Go to BATEE.com
Bryan's site can help you determine and confirm which part has failed.
As the poster above said, likely the controller, but there are multiple components that could cause this.

Not complex if the programmer or controller.
Check out his site.
He is THE BEST!

www.batee.com


Marty
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Old 07-25-2022   #4
CamP
 
Join Date: Jun 2012
Location: fort worth
Posts: 183
Default Re: AC blows out floor and defrost vents?

Quote:
Originally Posted by DRM500RUBYZR-1 View Post
That is the default mode when failed, so that you can see in the cold or wet when defrost or defog is required.

Go to BATEE.com
Bryan's site can help you determine and confirm which part has failed.
As the poster above said, likely the controller, but there are multiple components that could cause this.

Not complex if the programmer or controller.
Check out his site.
He is THE BEST!

www.batee.com


Marty
I spoke to Bryan. He thinks I have a vacuum issue because all my electronic control buttons work. Probably a simple problem that will be difficult to find.
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Old 07-25-2022   #5
secondchance
 
Join Date: Aug 2006
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Default Re: AC blows out floor and defrost vents?

Below Is QB93Z thread on replacing the programmer.
http://www.zr1.net/forum/showthread.php?t=27542

Jim as far as I know went in the deepest with HVAC diagnose and repair.
Reach out to Jim (QB93Z) and tap his knowledge.

Good luck!
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Old 07-25-2022   #6
CamP
 
Join Date: Jun 2012
Location: fort worth
Posts: 183
Default Re: AC blows out floor and defrost vents?

Quote:
Originally Posted by secondchance View Post
Below Is QB93Z thread on replacing the programmer.
http://www.zr1.net/forum/showthread.php?t=27542

Jim as far as I know went in the deepest with HVAC diagnose and repair.
Reach out to Jim (QB93Z) and tap his knowledge.

Good luck!
Thanks for that link. It appears that a kinked vacuum line under the passenger side hush panel fixed his similar issue.

I hope it's that easy! I replaced the ac programmer back in '97 and that job was no fun!
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Old 07-31-2022   #7
402Z
 
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Location: Florida
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Default Re: AC blows out floor and defrost vents?

I?m having the issue where I have cold ac but it only blows out of the foot and defroster vents. I?m guessing it is possible the HVAC programmer then?
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Old 04-05-2023   #8
CamP
 
Join Date: Jun 2012
Location: fort worth
Posts: 183
Default Re: AC blows out floor and defrost vents?

I never followed up on my vent issue. It turned out to be the vacuum line to the ac controller was pinched between the plenum and injector housing.
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Old 04-05-2023   #9
Young1
 
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Default Re: AC blows out floor and defrost vents?

That is correct. Cruise and AC share a common vacuum source on RH plenum. Secondaries vacuum source is the pump and LH plenum. Stuff under the hot plenum shrinks and ages and gets loose. Not as likely under the dash. I would also consult the FSM and follow the diagnostic tree. Vacuum stuff is pretty easy. Electrical not so much. Your patience and diligence keeps the legend alive.
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