AC Doesn't Blow In Face or On Floor

[RED TAHOE LS]

You may be right, although vacuum system has been around for a long time, biggest problem was with under hood vacuum tank (often called gorilla balls ) either leaking or leaking line. Just to many electronics on all makes/models today and very expensive for the consumer. JMHO and good luck, I'm from old school, very reliable.
David g..............

 

[rstewheck]

I became the proud owner is a 2003 SLT about 6 weeks ago and only two times have all the air vents actually worked. (Dual climate control)

The 2nd time it magically decided to work, I was on the road and it worked great for the duration of the drive (about 1 hour)...but of course when I restarted the Yukon a couple of hours later, it went back to not working

The other 99.9% of the time when either the AC or the heater are on, the fan only blows air through the defrost vents.

Anyone heard of this?

(Without the back AC vents all aimed at my head, I'd be way more uncomfortable)

Look on line, purchase a new damper control, switch the control and your problems will disappear.

 

[2011SSVHOE]

That blows my theory, I have never owned one and did not know, my bad.
David g...........

David I can tell you and I are old school I think they started to do away with the vacume in the late 80's

 

[Bonestock]

Look on line, purchase a new damper control, switch the control and your problems will disappear.

Damper control? My burb is still not working after replacing the hvac control head. I'll try the recal again but I guess all 4 actuators went bad at the same time.

OP did you ever get this fixed?

 

[Aaron_L]

My Suburban was doing the exact same thing as the OP, air only from the defrost vents. Before it actually stuck that way I would occasionally hear a popping sound in the lower dash area. Turns out that was the blend door actuator eating itself. I replaced the actuator & all is well. I think I invented a few new cuss words while doing the job.

 

[rstewheck]

I became the proud owner is a 2003 SLT about 6 weeks ago and only two times have all the air vents actually worked. (Dual climate control)

The 2nd time it magically decided to work, I was on the road and it worked great for the duration of the drive (about 1 hour)...but of course when I restarted the Yukon a couple of hours later, it went back to not working

The other 99.9% of the time when either the AC or the heater are on, the fan only blows air through the defrost vents.

Anyone heard of this?

(Without the back AC vents all aimed at my head, I'd be way more uncomfortable)

I have an 07 Yukon Denali and the passenger started blowing hot air. Replaced the damper actuator and the problem was resolved. Ebay price was $23.00 free shipping.

 

[shreksbrother]

I recently suffered from the same lack of being able to select where the air blew from (just fixed it this past weekend, actually). But I manually moved my selector to only blow out the vents.

For me the solution was the mode selector actuator. Despite trying the re-calibration, the mode actuator would only make a clicking sound and not move the gear. It is located above the accelerator pedal. It was fairly inexpensive (maybe $40 or so on Amazon), but you have to be a contortionist to remove/reinstall it. It is also important that the calibration marks line up on it before you install it. I found this out the hard way... On mine the calibration was off about 45 degrees, so it would not work properly. I had to remove it again, pop the cover off, remove a gear, and then line it back up.

It is important to follow the re-calibration portion afterwards.

I am happy to finally have the defroster option back.