JLoft

There is a choice on the second rocker switch from the right to open or close the wide vent in the dash. No matter which selection I make no air comes from the center vent, even if the fan is on high. What does everyone else see?

S5 Sportback, prestige, US model

N8!

I've always assumed it is for aesthetics and non-functional...

SYMAWD

It's a diffusion vent to help recreate natural airflow. It is functional even though you really can't feel the air blowing.

synergize

I don't get it, how it that possible?

saxplayer

The owner's manual makes it seem like more venting options you are opening (or closing).

I agree with the OP - nothing happens when I "open" it either. Not sure if I should leave it open or not.

JLoft

The manual is no help. All it says is "You can open or close the wide vent in the cockpit using the rocker switch (#5 in diagram)."

bluaudi

I am thinking maybe it means it opens / adjusts something behind the vent window that is out of sight and allows for more air flow or a change in the air flow throughout the car.
Maybe?!

Glisse

Hard to improve on SYMAWD's answer. Diffuse is the opposite from a directed air flow.

If you shut off all the other vents and turn up the fan, you will be able to feel some air flow from the wide vent.

The better question is whether it actually makes much difference. I don't think so. I suspect Audi wanted to be able to say it did "something", rather than say it was fake and just for design.

But then as car HVAC systems go, I think this one is pretty good. And the buttons (for the 3 zone system) are very cool

njspeedfreak

Yep - tried that some weeks back, and it definitely pushes some air, but not enough that you would feel it from a distance.

My guess is that during peak heating or cooling seasons (like now) you wouldn't notice anything because the blower needs to be cranked up high on the main vents just so the AC can keep up with the sun load coming through all the glass. But in the "between" seasons it might just be enough to allow the main vent fan to drop down a few notches so that you don't feel the breeze against your skin. And it probably has just enough circulation to work in situations where the temperature is already at it's set point but the humidity levels are still too high.