[ferocity02]

In my 07 E90, in between the two center vents, there is a knob that looks like it controls temperature. It has red on the right, and blue on the left. How does this relate to the temperature that I set on the HVAC unit itself? It it for fine tuning the temp of these two vents? I tried messing with it and didn't notice much difference in temperature.

[bernard54321]

Good question... lol

[alou]

Owners manual states: "Thumbwheel for more or less cool air from
the vents for the upper body area."

[Welcome to NBA Jam]

It helps control how fast you want the car to cool down or heat up. Windshield air vents go from warm to cool depending upon the temperature setting, while the main vents are fine-tuned by the driver to achieve the desired rate of temperature change. This is why if you have the temperature set all the way up, you'll feel hot air on your face from the windshield vent but cool air from the main vents.

[nynyny]

Pretty sure that's your cloaking device. Hard to find option in the 07's.

[ferocity02]

Originally Posted by Welcome to NBA Jam

It helps control how fast you want the car to cool down or heat up. Windshield air vents go from warm to cool depending upon the temperature setting, while the main vents are fine-tuned by the driver to achieve the desired rate of temperature change. This is why if you have the temperature set all the way up, you'll feel hot air on your face from the windshield vent but cool air from the main vents.

So this knob controls the temperature of the air that is blowing onto the windshield?

[PR3CI5N]

It adjust the temperature of the air blowing out of those two vents. So if for some reason you had your a/c blowing and wanted warm air out if just those two vents you can..not sure what their logic is behind it though

[jphughan]

The knob affects only the temperature of the air blowing out of the center vents. So for example if you want a cool cabin overall but want to keep your face warm, you can do that. Or (more likely) if you want a warm cabin overall but want to keep your face cool to avoid getting sleepy, you can do that too.

Page 109 of the 2011 3 Series manual. They don't publish those because they hate trees and want to create more cases of carpal tunnel syndrome, you know.

[dassub]

Originally Posted by PR3CI5N

It adjust the temperature of the air blowing out of those two vents. So if for some reason you had your a/c blowing and wanted warm air out if just those two vents you can..not sure what their logic is behind it though

Nope, when the a/c is on in the summer, setting it to the hot side still makes cold air coming in from the vents. It gets colder if you set it the other way, though.

The opposite only applies in the winter. When heat is on, you can have cold air from the vents.

[talisman311]

Use the search..

It adjusts the temp that hits your face. Put it on the cool setting during the winter time and you'll get cool air on your face rather than warm air that generally makes people drowsy.

[Welcome to NBA Jam]

Originally Posted by ferocity02

So this knob controls the temperature of the air that is blowing onto the windshield?

Onto your face

[NGEE]

Jeezus, had my car four years and never noticed that 'effing thing

[grzes]

ha ha ha, had the same question when I got my car, could not figure it out for some time but basically it is just for fine tune for the air that comes out of front vents and not only the center ones, at least in my car. If you A/C is working and you have it on the blue side then you get the same air flowing as HVAC unit is producing, turning it towards red it will mix with warm air so the air blowing directly at you will not be as cold. In the winter, if you have hot air blowing at you you can turn it towards blue and cold air from outside with me mixed up with the hot air so cooler air is blowing at you. In short, fine tuning of the air blowing at you directly.

[Dark_Knight_335]

It's the "charge an extra $5000 for absolutely no fucking reason" option. Seriously, I never noticed to do much of anything- then again I haven't paid really close attention to it either.

[StarReaver]

E9Xs have dual zone climate control. The driver's side and passenger's side temperatures can be adjusted separately. If you have your side set to cold (60deg), and your lady in the passenger seat has it set to warm (75deg) because girls are always cold, then turning that knob to the red square will make the large center vent blow warmer air. If it is turned to the blue square, it will blow cold air.

Doesn't make a difference if both temperature settings are even, but in the above case (or vice-versa) it is noticeable. Pretty useful feature if you ask me.

[MiniXP]

Originally Posted by StarReaver

E9Xs have dual zone climate control. The driver's side and passenger's side temperatures can be adjusted separately. If you have your side set to cold (60deg), and your lady in the passenger seat has it set to warm (75deg) because girls are always cold, then turning that knob to the red square will make the large center vent blow warmer air. If it is turned to the blue square, it will blow cold air.

Doesn't make a difference if both temperature settings are even, but in the above case (or vice-versa) it is noticeable. Pretty useful feature if you ask me.

It will change the temp even if both sides are set to the same, although it would be most noticeable in the winter. My e46 with only single zone climate control also had this.

As other people have said, it is there so that you can have cold air blowing on your face and warm air on your feet to keep you awake.

I find it kind of nice sometimes, but most of the time I wish it wasn't there as it is just 1 more thing to adjust.

[GB-335xiCoupe]

I have never even changed mine. Now I'll have to experiment. Thanks, Ferocity02 - something else to distract my driving.

[dassub]

Originally Posted by StarReaver

E9Xs have dual zone climate control. The driver's side and passenger's side temperatures can be adjusted separately. If you have your side set to cold (60deg), and your lady in the passenger seat has it set to warm (75deg) because girls are always cold, then turning that knob to the red square will make the large center vent blow warmer air. If it is turned to the blue square, it will blow cold air.

Doesn't make a difference if both temperature settings are even, but in the above case (or vice-versa) it is noticeable. Pretty useful feature if you ask me.

The dual climate control is a blessing on this car. I set mine to 19 degrees Celsius in the winter, while the wife sets hers to 25 or something. Although, I do use the max seat warmer setting, which is HOT.

['02onthebrain]

And your passengers in the rear get this super awesome rather useless feature as well from their vents!

You can notice it in the summer when you are cranking max AC and those vents are slightly less cold. I thought there was something wrong with my AC charge only to realize the knob was all the way to the red.

[alou]

My guess is that it mixes in some ambient air to either cool the air (when blowing warm heater air) or warm the air (when blowing cold A/C).

[jcarv20s]

This is going to sound stupid but, lets say I have it set at 72 and it's on the blue side, it seems like a cool 72, on the red side it seems like a warm 72. Sounds even more stupid typing it but try it you'll see.

[SHEEDI]

That button is for............