# Footwell - Cabin Temperature Differential Button?



## PanEuropean (Nov 3, 2001)

Can anyone tell me what the button in the photo below actually does?
The owner's manual says nothing about it, anywhere. The Quick Reference Guide (fold out pamphlet in the pocket of the owner's manual) identifies it as a "Temperature Control for Center Air Vents". The Phaeton Service Manual (on CD) identifies it as a "Footwell - Cabin Temperature Differential Button", which suggests to me that it might have a bigger purpose than just adjusting the temperature of what comes out the center vents, if the center vents are open.
I note that I can adjust the setting on this button even if the system is in AUTO mode, and the center vents are closed. This is confirmed by the movement of the little red light underneath it from one side to the other.
Has anyone figured it out?
Michael
*Mystery button on center console*








*Nomenclature from Phaeton Service Manual*


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## dtwphaeton (Sep 7, 2004)

*Re: Footwell - Cabin Temperature Differential Button? (PanEuropean)*

You are right that you certainly cannot figure it out from the manual. In my orientation, I was told that it is for selecting whether the center vent airflow is -- in relative terms -- warmer or cooler than the rest of the airflow. It was likened to the old "bi-level" setting on some domestic cars, where you could select to have warmer air at your feet for comfort, but cooler air at your face level to stay fresher. This made sense, and indeed that is what seems to happen, but it's hard to confirm.


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## PanEuropean (Nov 3, 2001)

*Re: Footwell - Cabin Temperature Differential Button? (dtwphaeton)*

Thanks for the answers, guys.
RMG, I hadn't even noticed the additional functionality you mentioned (the light changing colour from blue to red). I really appreciate you pointing that out.
DTW, I think you have it pegged - your explanation is consistent with the repair manual nomenclature for the button - now, the unanswered part of the question is: What gets modified? In other words, if the cabin temperature is set to 21° (on AUTO, with all regions set to the same temperature), and the driver presses the mystery button, does the center vent temperature change up or down from 21° while the footwell air output remains constant at 21°?
Michael


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## trekguy (Aug 16, 2004)

*Re: Footwell - Cabin Temperature Differential Button? (PanEuropean)*

ps
Mercedes_Benz has has that center-vent heating/cooling control button for several years.


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## rmg2 (Jan 23, 2004)

*Re: Footwell - Cabin Temperature Differential Button? (PanEuropean)*


_Quote, originally posted by *PanEuropean* »_Thanks for the answers, guys.
RMG, I hadn't even noticed the additional functionality you mentioned (the light changing colour from blue to red). I really appreciate you pointing that out.
DTW, I think you have it pegged - your explanation is consistent with the repair manual nomenclature for the button - now, the unanswered part of the question is: What gets modified? In other words, if the cabin temperature is set to 21° (on AUTO, with all regions set to the same temperature), and the driver presses the mystery button, does the center vent temperature change up or down from 21° while the footwell air output remains constant at 21°?
Michael

You're welcome!
I'm not sure if the color changes because of the temp settings in the infotainment system or as dtwphaeton mentioned.
I have my car set at 70 degrees front and back and I never change it (unless the wife gets a hot flash







)
I do recall seeing it red back in March when we had an extremely cool day. In that case it seemed that the heater came on in order to bring the temp to 70 degrees thus the red light came on.
We're getting closer to colder weather here in So. Cal so I'll keep an eye on it.
You're probably in a better position to see it change given you're up in Canada. Therefore, I'm sure you'll have a report before me.


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## PanEuropean (Nov 3, 2001)

*Re: Footwell - Cabin Temperature Differential Button? (rmg2)*

RMG:
Well, try not to laugh too much at this - but I didn't know it had the ability to be blue, all I have ever seen since I got the car (two weeks ago) is a red light towards the right hand end of it.
Now, I gotta go work on my snow tire thread....








Michael


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## rmg2 (Jan 23, 2004)

*Re: Footwell - Cabin Temperature Differential Button? (PanEuropean)*


_Quote, originally posted by *PanEuropean* »_RMG:
Well, try not to laugh too much at this - but I didn't know it had the ability to be blue, all I have ever seen since I got the car (two weeks ago) is a red light towards the right hand end of it.
Now, I gotta go work on my snow tire thread....








Michael

Guess we'll be waiting until Spring for your report to see if it turns Blue.


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## PassaTT (May 24, 2003)

*Re: Footwell - Cabin Temperature Differential Button? (rmg2)*

If this is the button I am thinking of, then I don't think it changes temperature, I think it changes airflow. Far blue is all open and far red is all closed (or was it the other way?).
Here's a test.
With the car running, set your climate to some reasonable temp so you can tell hot or cold diferential. On the climate screen push the Center Manual Flow button for one or both sides. By center, I mean not the up and not the down. The vents will motor open.
Now, start to play with that rocker button and the airflow will either increase or decrease in response to the level of the button pushes.


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## bobschneider (Oct 12, 2004)

*Re: Footwell - Cabin Temperature Differential Button? (PassaTT)*

In my wife's BMW, there's a similar control on the center vents. Turning it towards blue makes the air from those vents cooler than the rest of the airflow, turning it towards red makes it warmer.
I haven't really experimented with this on the Phaeton, because since I got it it's rarely been warm enough for the dash vents to open


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## PanEuropean (Nov 3, 2001)

*Re: Footwell - Cabin Temperature Differential Button? (bobschneider)*


_Quote, originally posted by *bobschneider* »_...since I got it it's rarely been warm enough for the dash vents to open

I notice your city is right on the lake in Illinois - heck, that almost qualifies you as an "honorary Canadian" so far as cold weather goes. I'll let you know when we start our group buy on snow shovels and ice scrapers...








Michael


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## FalconerHK (May 18, 2004)

*Re: Footwell - Cabin Temperature Differential Button? (PanEuropean)*

I didn't recall anything in the manual about it either, but I have found that it seems to regulate the speed at which the climate control regulates temperature, even with the direct vents closed.
Normally, I will leave it in the middle (LED off) position, but it the sun is shining on me and my skin feels a bit warm, clicking the blue dot until the blue LED is in the far-left position directs more cool air from the indirect vents in the dash.
In a nutshell, I use it as a way to "fine tune" the air temperature coming from the indirect dashboard vents.
Hope this helps.


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## PanEuropean (Nov 3, 2001)

*Re: Footwell - Cabin Temperature Differential Button? (dtwphaeton)*


_Quote, originally posted by *dtwphaeton* »_In my orientation, I was told that it is for selecting whether the center vent airflow is -- in relative terms -- warmer or cooler than the rest of the airflow. It was likened to the old "bi-level" setting on some domestic cars, where you could select to have warmer air at your feet for comfort, but cooler air at your face level to stay fresher.

Found out today that DTW was 100% correct with this answer. The driver can push the button in either direction to make the air coming out of the mid level vents (either the perforated dashboard or the louvered vents, if the decor doors are open) warmer or colder than the temperature set on the display screen. The indicator lights underneath the button will indicate blue if it is biased towards colder air from the mid-level vents, red if it is biased towards warmer air, or, no lights at all if no differential has been set.
Michael


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## derrickonline (Feb 9, 2008)

*Air recirculation*

I've noticed warm air in my phaeton while driving even though the air fan speed is set to off (dial turned all the way to left). In most cars hitting the air recirculation button keeps outside air from enerering the cabin. However with air off the air recirculation option is not illuminated.
any ideas on how to shut air off period. Even outside air (which in my case is being warmed to the temp set on my air controls before I shut it off). Am I making any sense? I hope I am.


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## mhoepfin (Dec 20, 2007)

Hi Derrick,
Make sure you don't have the bi-level switch all the way to the red. It's the one in the middle of the dash that goes from red (hot) to blue (cold). That may be it.
That switch is actually one of my favorite features of the Phaeton as I can always have some cool air blowing around my face.


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## derrickonline (Feb 9, 2008)

*Re: (mhoepfin)*

Hmmmm...I never touch that...I think I will test it on my rush hour commute tomorrow. But the air seems to come from beneath (since I keep my vents covered). I will still give it a shot. Thank you.


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## PanEuropean (Nov 3, 2001)

*Re: (mhoepfin)*


_Quote, originally posted by *mhoepfin* »_That switch is actually one of my favorite features of the Phaeton as I can always have some cool air blowing around my face.

Mike:
I have never quite figured out how to use that control (the bi-level heating rocker switch). I know what it is supposed to do, but I don't know which direction one is supposed to move it in order to get a certain result. For example, if you move it all the way to the 'red' position, what happens?
May I trouble you for a "Bi-Level Switch for Dummies" type of explanation?
Thanks,
Michael


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## VWVictoria (Oct 1, 2007)

*Re: (PanEuropean)*

HI Michael, I have been experimenting with that rocker switch and if it is all the way into the blue the air coming out is a bit colder than what is coming out everywhere else if it is off the temp is the same and if it is red it's warmer. Kind of a "cool" feature
Jeff


_Modified by VWVictoria at 12:59 AM 4-15-2008_


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## PanEuropean (Nov 3, 2001)

*Re: (VWVictoria)*

Jeff:
Which outlet does the rocker switch modify the flow from? I comprehend that blue = cool and red = warm, but where do you notice the effect? From the footwell outlets, or the mid-level (dashboard) outlets? In other words, if you move the switch all the way to the red position, where does the warmest air get delivered?
Michael


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## Realist42 (May 14, 2006)

*Re: (PanEuropean)*


_Quote, originally posted by *PanEuropean* »_Jeff:
Which outlet does the rocker switch modify the flow from? I comprehend that blue = cool and red = warm, but where do you notice the effect? From the footwell outlets, or the mid-level (dashboard) outlets? In other words, if you move the switch all the way to the red position, where does the warmest air get delivered?
Michael

Michael,
As far as I have noticed, it modifies the climate zone that is where your head sits in, as all cars (with automatic climate control) have two climates zones (at least) in the vertical as there is a need to keep the head cooler than the rest of the body and often the feet a great deal warmer. If our heads gets too warm we tend to get very sleepy... 
So, it is modifies the delta between the top vertical temperature zone and the overall temperature setting for the horizontal zone setting for the car that you sit in.
But then that is a generic override so I guess it modifies all zones with the same amount, so if you passenger has there side set 3 degrees C above yours, do their side also get warmer??
I often find myself wondering how one keeps a system like that from running amok...
rgds
J

_Modified by Realist42 at 1:11 AM 4-15-2008_


_Modified by Realist42 at 5:09 AM 4-15-2008_


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## mhoepfin (Dec 20, 2007)

Granted, I keep it in the Blue position, but the air comes out of the hidden vents near the windshield and not from the closed dash vents.
So, say it's 60 outside and very little airflow in the car and the vents are in the closed position, I still feel cool ambient air around my head. Certainly not blowing in my face, but you can definitely feel it.
Same on cold days, I'll have heat coming out of the foot vents but still feel a more balanced air around my head.
Sounds like an odd description, but that's how I've found it works. I haven't run it in the Red, but I would imagine that cooler air would turn into a less cool air.
In a nutshell, there are people who always want some type of air flow, and I imagine this is exactly what this is for.


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## Rowayton (May 29, 2004)

*Re: (mhoepfin)*

This post made me pull out the manual. That sure cleared everything up







. If someone like Michael is having trouble understanding the operation of that control perhaps an English speaking engineer in Dresden could chime in with a non VW owner manuals description of the controls operation. Gotta run and start pushing buttons like the rest of you







.


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## chrisj428 (Feb 26, 2005)

*Re: (mhoepfin)*

Mike,
I don't think VW is going to allow you to cut off all air inside the vehicle with the climate control off.
If the system is monitoring and controlling interior conditions, then it will allow outside air to be switched off. 
However, if the system is not controlling interior conditions, it's not going to let you cut off air circulation to the cabin.
I'm sure there's a safety reason behind it.


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## VWVictoria (Oct 1, 2007)

*Re: (PanEuropean)*

this would be a great application for one of those point and shoot instant read thermometers, does anyone have access to one?
Jeff


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## CA_W12 (Mar 22, 2007)

*Re: (PanEuropean)*

WOW... I am stumped! there is a feature on the Pheaton Michael does not know all the intricate details and he has not yet torn it apart to figure it out????








But I agree, it does not work as well as in the A8 (D2) - there was a simple thumbwheel which was all I ever needed to adjust to get the perfect A/C setting: In the morning, after a hot shower a small adjustment to the cold side, in the evening a small adjustment in the opposite direction to compensate for a minute desire for a warmer temperature. Worked perfect.


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## chrisj428 (Feb 26, 2005)

*Re: (CA_W12)*


_Quote, originally posted by *CA_W12* »_there is a feature on the Pheaton Michael does not know all the intricate details and he has not yet torn it apart to figure it out????

That's because, when the vehicle is assembled, Hans places the HVAC unit in the center of a room and then a number of Bavarian putzfraus poke their appointed workers with long sticks and they proceed to assemble the vehicle around it. 
At least that's the way it seemed to be on my 300E...


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## W126C (Jan 27, 2005)

*Re: (chrisj428)*


_Quote, originally posted by *chrisj428* »_That's because, when the vehicle is assembled, Hans places the HVAC unit in the center of a room and then a number of Bavarian putzfraus poke their appointed workers with long sticks and they proceed to assemble the vehicle around it. 
At least that's the way it seemed to be on my 300E... 

*OUCH!*








Regards,
Brent


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## derrickonline (Feb 9, 2008)

it seems adjusting that red to blue switch under the vents doesn't work. I still feel continuous airflow at my feet even when air/climate control is off.
For the poster who said its probably a safety reason I would beg to differ. All of my other vehicleswould allow me to prevent outside air from entering my vehicle. This car seems to keep a constant flow of air at my feet and its too warm!
The only way to get around it from what I've seem is to put climate control on and set desired temp which then adjusts that foot air flow.


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## murphybaileysam (Dec 29, 2005)

*Re: (derrickonline)*

I recall asking the Phaeton tech people about this. I always like to just have outside air coming through the vents on cool spring days rather than the climate control always on. I was told that the car was designed to leave the climate control set at the most comfortable temperature and leave it on at all times. It is like the sound system which is never powered off, just muted.
As far as outside air entering the cabin.....when driving through areas where there are noxious odors, refinery smells etc. you should be able to just recirculate the cabin air without drawing outside air in.


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## Prince Ludwig (Mar 24, 2007)

Derrick, 
Just out of curiosity, what is it that you're trying to achieve by turning off the AC?
If you could bear to have it at the minimum fan setting (rather than turning it off completely) and choosing indirect ventilation manually it might stop air coming out of the footwell in favour of the top dash vents.
Harry


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## Rowayton (May 29, 2004)

*Re: (Prince Ludwig)*

Derrick,
Get into the "Climate" menu on your center display and punch up just the upper registers (left and right sides) and see if any air still circulates from the foot wells. In the 'Auto' mode the system dictates what it believes is the most appropriate comfort setting for the environment the car is operating in. If that doesn't work perhaps a register door (foot wells) could be malfunctioning. Just a guess but worth a button push or two.
RB


_Modified by Rowayton at 4:41 AM 4-18-2008_


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## chrisj428 (Feb 26, 2005)

*Re: (derrickonline)*


_Quote, originally posted by *derrickonline* »_For the poster who said its probably a safety reason I would beg to differ.

Oh. Ok.


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## derrickonline (Feb 9, 2008)

*Re: (chrisj428)*

I believe based on the information I'm reading that I'm stuck with keeping the climate control on (just at a comfortable temp) to regulate the air since you can just shut it off. 
As the poster who mentioned it works similar to the radio, keep it on and at the desired temp seems to be what I'm finding.
What I do realize is if I set the desired temp in the card to say 70 then shut the climate control off, the air I feel coming through the footwells is at 70 and barely comes out since outside is probably 70 something degrees. Hope that made sense. 
Thanks to all for the info.


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## PanEuropean (Nov 3, 2001)

Photos re-hosted.

Michael


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## geoffrey_fake (Dec 2, 2011)

the center button that goes from color blue to red, its to adjust 2 points.

The first one is the air-flow that comes from all the grill that is on top of the dash board, if you put the button in blue, it will come cold air in red - hot air, this is only in case you have disturbances because of too much heat coming from the front window, for example in a very hot shinny day.
You set your Clima to your set points and you enjoy as it is, if suddenly you fell a bit warm ( we know all that the warm are always up and cold always down) then you just move a bit that center button to cold it down a bit, without being obliged to change all the settings in the clim control.
This is In SUMMER and HOT DAYS.

Now in winter, its the other way around with a difference !!! I did my self the test many times
I leave in Luxembourg and we have hot in summer and quite cold in winter ( -15 degrees Celsius or more (5 or less Fahrenheit) 

so what happen when I go with that center button to the must hot point ( red light) ? of course you fell warm coming from the grill on top of the dash board, BUT ALSO, from under the seats ( front seats goes also to rear seats, and it warms up all the ground carpet, you can take your shoes out and relax your feet on the carpet, its warm and nicely, also it drys all snow or humidity specially in winter. 

In winter as the cold air its more heavy then warm air, generally it goes straight to the ground, and so its very often that in other cars its bloody cold and the carpet also, however you can adjust the air-flow to warm up that feet area but its not so pleasant, it comes too hot or too cold and you are disturbed by a high air-flow etc, in the phaeton of course you can in urgency chose the air-flow to go down and warm up all feet etc, but you have to adjust and do a few settings in the clima control, but its very very rare, with that center button you adjust to the red side and you will fell nothing no air-flow disturbing or too much hot temperature, or any other disturbance, its all quite and nicely and warm.

they call that here in Europe a " heated floor" like in a house with heated floors, no blow air no noise, just all warm. 

thanks that meddle button.


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## Paximus (Aug 26, 2011)

I have been puzzling over the exact action of that button in the last few weeks. Of course I read this post about it, and possibly others, but your explanation makes a lot of sense as to how one might design it to perform.

Thanks! I will have a play now that the days are sometimes colder and sometimes warmer! :thumbup:

Chris


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## Gabs08PHTN (Jan 6, 2011)

Paximus said:


> Thanks! I will have a play now that the days are sometimes colder and sometimes warmer! :thumbup:
> 
> Chris


We are suffering the same sort of "summutumn"  in here, so it is a good time to play with that button.

Gabriel


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## Beastmode6.0 (Jan 8, 2013)

*Motorized Vents*

Is there a thread on the dismantle and repair of this system? I can't imagine the charge from a VW dealer. Is the system just behind the wood-grain ? Diagrams would be helpful.


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## Paximus (Aug 26, 2011)

Hi, 

Some of the components of the air system are relatively accessible from the engine compartment, others behind the dash panel have workshop instructions that start with "remove seat headrests, remove rear seat cushion..." (and that's just to start to remove the dash panel). You can see from the simple diagrams below that the entire unit is moderately large and deeply embedded between the cabin and the plenum chamber across the firewall. 

You really need a workshop manual and a spacious, dry workshop to attempt to replace some of the motors. However, I seem to recall that some owners have changed the air intake and recirculation flap motors. 

The air vent cover motors can be serviced with a little less dismantling. See these threads: 
How to remove the front wooden panel with the chrome clockring 
Cleaning repairing wood trim dash 
Instrument Panel air vent cover (decor-panel) stays open does not close when it should - added to TOC 


Chris 



*Heating unit is deeply embedded* 








image (c) Volkswagen 


*There are 15 flap motors in the unit, plus more external to it* 








image (c) Volkswagen


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## PanEuropean (Nov 3, 2001)

Beastmode6.0 said:


> Is there a thread on the dismantle and repair of this system?


 Uh, I hate to be the one to tell you this, but when VW builds a Phaeton, the very first part they install into the bodyshell is the HVAC system illustrated above. Everything else, including the engine, gets added later. 

You don't even want to _THINK _about removing the HVAC system. 

Michael


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## johnnyjiang (Feb 24, 2014)

hi Michael,
this is what i found recently in the handbook. Not sure if you already saw it or not. But anyway I think it is an answer for the question.


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## Paximus (Aug 26, 2011)

Hi Johnny,

Thanks for putting up the photos listing the button description. As the posts in this thread conclude, that button is not simply the equivalent of the manual slider that you get on some car air vents to control the heat or cold air flow.

In my simple tests, I found that it alters the balance between the heat supplied by the centre vents and the heat supplied to the footwell. So if I have cold feet, I set that vent button towards the blue end, which lowers the temperature of the upper cabin air directed at face level and increases heat in the footwells. The amount of heat delivered to the cabin overall stays the same, to maintain the selected perceived temperature as entered in the big central display.

That's the way mine works. It's a 'cold feet button' for me. 

Chris


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## phaetonjohn (Oct 24, 2014)

Hello,
That switch controls the CENTER VENT (only that vent's) temperature, regardless of what you have the temperature set as. For example, if you have your heat setting at 73 degrees F, and the dash vents are open (the only time that switch is useful. If the center vent isn't open, then that switch WILL NOT change anything.), and you have the blue side of that switch all the way to the left (cold), then the air coming out of that center vent will be about 67 degrees F. Also, if you have the red side of that switch all the way to the right (HOT) , then the air coming out of that center vent will be about 81 degrees F.

-John


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## cbh123 (Aug 25, 2013)

Every German car since the late 1970's (some earlier) have hade this feature.
It is nothing new or innovative for the phaeton. 

The entire concept is to create a stratosfied atmosphere - comfortable temperature for the body, but cooler air directed at the face. The science is that a cooler face will increase alertness and therefore safety.

At some point in the 1980's the American consumer started noticing the cooler air at the face, and started to complain. The German response to this varied, some cars having individual shut off for the offending (to Americans) cold air, and higher end cars with a dial to choose the - "alertness" factor.

It is funny, decades of hopeless training, hopeless delivery explanations, and crappy owner's manual explanations have kept this ever so simple concept a mystery to the masses.

There is proven science and countless studies done that prove that a controlled atmosphere will reduce accidents, but the general public will not listen or accept it... Such is the life of science. (Is the world flat still for some people?) 

If I hypothesize about how we all become so crybaby-ish about this, I wonder about the silly baby strollers with the plastic bubbles over them. I hear the parents start teaching from age zero "ohhhh.... Dear.... Child.... Feel that AWFUL cold air. " "better put a cover up..." 

Imagine if the parents of the world chose to say "isn't that fresh clean air a WONDERFUL feeling my child?) 

So.... If you believe that science can keep you alert... Keep that adjustment in the middle.

If you think that a little bit of slightly cooler air is actually harmful, go ahead and play with the adjustment. 

Hahaha.... Don't kill me for speaking the truth.


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## phaetonjohn (Oct 24, 2014)

Amen.

Amen.


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## maccd87 (Dec 20, 2015)

phaetonjohn said:


> Hello,
> That switch controls the CENTER VENT (only that vent's) temperature, regardless of what you have the temperature set as. For example, if you have your heat setting at 73 degrees F, and the dash vents are open (the only time that switch is useful. If the center vent isn't open, then that switch WILL NOT change anything.), and you have the blue side of that switch all the way to the left (cold), then the air coming out of that center vent will be about 67 degrees F. Also, if you have the red side of that switch all the way to the right (HOT) , then the air coming out of that center vent will be about 81 degrees F.
> 
> -John


In my experience this seems to be very true. On a longer drive to and from Chicago this weekend, I found that my feet were extremely warm. But my upper body was comfortable. In automatic mode the center vents remain closed. Pushing this all the way to Cold (Blue) and Red (Hot) made and leaving it for 10-15min each, made no impact. Leaving me to believe that this button only impacts the center vents which were not open at the time. 

Now, I'm in the spoiled category here, but is there any way to get the climate control to be less aggressive with heating at your feet? Maybe this is a Vag-Com tweak to one of the HVAC controllers?


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## phaetonjohn (Oct 24, 2014)

maccd87 said:


> In my experience this seems to be very true. On a longer drive to and from Chicago this weekend, I found that my feet were extremely warm. But my upper body was comfortable. In automatic mode the center vents remain closed. Pushing this all the way to Cold (Blue) and Red (Hot) made and leaving it for 10-15min each, made no impact. Leaving me to believe that this button only impacts the center vents which were not open at the time.
> 
> Now, I'm in the spoiled category here, but is there any way to get the climate control to be less aggressive with heating at your feet? Maybe this is a Vag-Com tweak to one of the HVAC controllers?


I've never noticed that my feet have been too hot. I leave mine at 20.5 C, and I'm always comfortable.

The button only affects the centre vents. It only works if vents are open. It's an override. Everything else stays under automatic, except for the centre vent temperature.

It's in the manual. AND the quick start guide.

-John


Sent from my iPad using Tapatalk


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## cbh123 (Aug 25, 2013)

I'm 99% certain the "stratified" atmosphere is controlled no matter what. 
The centre vents only open when the perforated dash top is unable to keep the climat just right.
As long as the system is in auto, the system will keep the foot wells slightly warmer all the time. 
If it is winter, there will be cool upper body air just because of the doors provide better insulation than the windows. It will add warm air gently the through the perforated dash in the winter just until the upper/lower temps are right. 

There is no simple way to describe the operation,,there are a dozen sensors, and flaps, and settings that will mix and match the air out of dozens of air outlets. 


If your feet are too warm, make sure you are in full auto, adjust the main temp setting for,happy feet, then you can set the red/blue setting to red.. And see if that helps


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## Paximus (Aug 26, 2011)

There is a perhaps unexpected effect of changing that centre vent air temperature setting.

The gross heat fed into the cabin is a function of the little temperature sensor embedded in the centre console, the one with a fan in it to achieve a faster response time. It's part of the main climate control loop.

Therefore, if the centre vent temperature is turned down using the red/blue control to cool the face, the cabin temperature will tend to fall slightly. This will be detected by the temperature sensor, which will cause a slight increase in the gross amount of heat from the system. This will cause the footwell temperature to rise slightly.

The net result is that *manually turning down the centre vent's air temperature to cool the face will also slightly warm the feet* and vice versa, once the system has re-stabilised. The overall cabin temperature will continue to meet the Auto setting, say 20.5C.

Chris


*Michael's (PanEuropean's) photo of the fan sensor location*


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