AC blows out the bottom vent

[L82Vette]

My AC blows out the bottom vent and not through the vents in the dash. Has anybody seen this or know what could be tha problem.
thanks

Lou

 

[Bob Chadwick]

Your vacuum is not changing the diverter from the lower to the upper positions. I had the same problem and after confirming that the hardware was in place and that the vacuum actuator was working, fixed the problem by changing the switch/slide hardware. Evidently the small plastic parts can fail over time and not allow for the slider to divert the vacuum to the right port, which then prevents the actuator from changing the position of the door inside the system.

I have put together a web page that explains how most of this stuff works. http://home.attbi.com/~jchadwick/ventilation.htm

 

[page62]

Either that or part of your ducts are missing. Check under the dash to see if the ducts to your lower vents are still there...

 

[L82Vette]

Thanks for the information, I'll check it out

 

[Greekman]

Mine is doing the same?....

When my A/C is on the cold air is also coming out the floor vents like where the heater hot air should come from?

Mine was working fine until I got my car back from the Chevrolet Dealership after wiring a factory radio that I had installed.

Could they have possibly left something dis-connected?

Any thoughts on this?

I don't think they removed the heater/ A/C switch panel in the console, but I guess it is possible.

Thanks in advance for any and all responses.


.

 

[Bob Chadwick]

The controls are right there below the radio and the actuator is the left of the area so it is possible.

Do you have vacuum to the actuator when you change the position of the slider? If not, pull one of the trans tunnel covers off and take a quick look and make sure your vacuum lines are connected securely.

Here is the actual vacuum diagram, at least for a 77

 

[joe1975]

Is there no flow or almost no flow?

 

[Greekman]

Joe1975, no not much air flow either? Like it disappears somewhere?

 

[joe1975]

Yep! thinking of the C-4 motor swap.

 

[Bob Chadwick]

I took a bunch of pictures of the blower motor on a car I saw at Carlisle that had the fender off and the parts all exposed. I'll get those posted later this week if you're interested in taking a look.

 

[George Black]

Bob: Yes, I would like to see the photos! Knowing exactly what is behind the fender makes it easier for me to "visualize" what repair/fix is needed. Thanks, George B.

 

[Bob Chadwick]

The pictures are posted on my web site.

 

[George Black]

The pictures are posted on my web site.

Bob: Thank you for posting the photos!

 

[Bob Chadwick]

Hope it helps. Post some pics and step by step as you pull it apart. I got my instructions from some one else and looking at my car it seems like would be easier than that.