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1999 Deville
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13 Posts
Discussion Starter #1
Hello I own a 1999 Cadillac Deville and I’m wondering why I only get air through the defroster and not the actual vents. A while back I had air flow blowing through the vents but it stopped. I switched one blend door actuator on the passenger side under the dash but didn’t seem to fix it. Please help I don’t know if there’s another one I need to switch
 

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Registered
2002 Deville and 2009 DTS
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482 Posts
I am not sure about the 1999, but I think there are 3 blend doors.
1 on the passenger side and 2 on the driver side.
 

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Super Moderator
White Diamond '03 DHS (with DTS floor shift)
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86,468 Posts
The pre-2000 Deville's get air from the dash vent ONLY when in the A/C mode.
Heat comes from the floor vents or windshield vents.
Check your owners manual.
 

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1999 Deville
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13 Posts
Discussion Starter #5
The pre-2000 Deville's get air from the dash vent ONLY when in the A/C mode.
Heat comes from the floor vents or windshield vents.
Check your owners manual.
I don’t have the owners manual but I haven’t found anything that it only blows from the defroster or floor vents.
So what your saying is that it’s normal for it to come out from only those or should I look into the second actuator
 

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Registered
2002 Deville and 2009 DTS
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482 Posts
There is at 2nd actuator... look at the pictures I attached previously.
Look at the parts in red circles...# 5 and #25
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
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18,999 Posts
your 1999 Deville still has the hybrid system -
electric actuators control the TEMPERATURE -
vacuum motors control MODE - WHERE the air blows from -

also - this is a fully automatic climate control system - except DEFROST -
meaning it was designed for you to simply set the desired cabin temperature
and the system would control the airflow to maintain that set temp -

depending on AMBIENT temperature -
HEAT is discharged from the floor vents -
AMBIENT and COOLED air is discharged through the center vents -

HOWEVER - if there is a vacuum leak -
the MODE will DEFAULT to the DEFROSTER position -

SO - if you select a higher than ambient temperature -
BUT you only get heat from the defroster -
either you have a vacuum leak - OR the vacuum motor controlling MODE is defective -
 
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