A/C blows out defrost only

1999 BUICK PARK AVENUE
242,296 MILES • 3.8L • 6 CYL • 2WD • AUTOMATIC
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K9NIINE1966
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It is a little low on A/C juice, but everything blows out of the defrost we put it on vent and still out the defrost, we put it on floor and still out the dash. Same when we put it on the heat. Any one have a problem like this and how can I fix it?
Jul 11, 2018 at 11:14 AM
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DANNY L
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Hello, I am Danny.

I am attaching a link for you to see to get started on the diagnosis of your system. Hope this helps and feel free to ask any questions if needed. Thanks for using 2CarPros.
Danny-

https://www.2carpros.com/articles/air-vents-stay-in-the-defrost-position
Jul 11, 2018 at 5:09 PM
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K9NIINE1966
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Hay Danny, thank you for the fast reply. Yea, we have a llay out of the dash we got from the dealership they was nice to send us one. I see it dose have four actuators in there looks like it is a whole dash removal. I guess we will be checking the heater core and the EVAP core while we are in there. I am sure its a dirty.
Jul 12, 2018 at 5:45 AM
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DANNY L
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Hello again.

Here is a picture and the location of the two air mix actuators. Hope this helps and feel free to ask any more questions if needed. Thanks for using 2CarPros.
Danny-
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Jul 12, 2018 at 5:02 PM
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K9NIINE1966
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Okay, now that we have put both actuators on the driver side part numbers 89018375 and 89018383, the air now blows likes it is supposed to. Defrost vents floor all work great but now we have ice cold on passenger side and kind of cold on driver side. Could the main A/C heat controller on the dash be affecting this. I tried to upload a picture, but I do not know if it worked.
Jul 13, 2018 at 10:07 AM
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K9NIINE1966
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This unit.
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Jul 13, 2018 at 10:08 AM
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STRAILER
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You can try to recalibrate the unit by removing the A/C and HVAC fuse with the key on for five minutes which is located in the fuse panel. Check out the diagrams (below). Please let us know what happens.

Cheers, Ken
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Jul 16, 2018 at 10:58 AM