Center air outlet buttons (blue/red) - purpose?
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Center air outlet buttons (blue/red) - purpose?
Can anybody tell me in short what do these buttons do: "Heated air supply button (blue)" and "Non-heated /cooled air supply button (red)". That is how they are named in the manual.
When I press them I see the small LED's going on (red/blue - respectively) but I was never trying to investigate what actually happens as a result. Is it about the center outlets starting to work? And if the buttons are not "on", the outlets are nearly closed?
How (if at all) does it relate to the settings in the A/C control panel?
The manual says nothing (in my understanding).
When I press them I see the small LED's going on (red/blue - respectively) but I was never trying to investigate what actually happens as a result. Is it about the center outlets starting to work? And if the buttons are not "on", the outlets are nearly closed?
How (if at all) does it relate to the settings in the A/C control panel?
The manual says nothing (in my understanding).
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Joined: Apr 2004
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1997 S600 Sedan
Also, you don't get the option to direct air to the center vent when in manual control mode unless one of the buttons is pressed. In auto mode, the climate control uses the center vent when it thinks it should.
Brett
Brett
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Joined: Jun 2005
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From: Oslo, Norway
1998 C140 CL500
pressed, the center vent only outputs air with hot or cold air if
that is whats coming from the rest of the unit. So, if red
button is pressed, and the climate is hot and the A/C is on, no
air is coming thru the center vent. Opposite, in winter, when
the outside is cold, having the blue button pressed, no air
will come thru, because the air supply from the unit is hot.
Or have I misunderstood?
br,
syljua
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well... I am still a bit confused after these various statements 
. but anyway - i will obviously try. and am I correct if I would say, in simple words, based on your explanations, that the role of these buttons is a kind of choosing what type ("temperaure: hot or cold") of air is only allowed trough these vents? 
. but anyway - i will obviously try. and am I correct if I would say, in simple words, based on your explanations, that the role of these buttons is a kind of choosing what type ("temperaure: hot or cold") of air is only allowed trough these vents?
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Joined: Jun 2005
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From: Oslo, Norway
1998 C140 CL500
I have tried it myself, and have to correct my statement.
At least now, when the weather is cold. Pressing none will
give no air. Pressing the red will give the hot air
that the rest of the vents have. Pressing blue will give
fresh air.
br,
syljua
At least now, when the weather is cold. Pressing none will
give no air. Pressing the red will give the hot air
that the rest of the vents have. Pressing blue will give
fresh air.
br,
syljua
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From: Dallas
1996 S500 Sedan
The blue is for "fresh air" regardless of interior/outside temperature... this allows fresh, cool air in the winter when the heated air can get stuffy. The red button passes slightly heated air through the center vents, so if it gets to -20 degrees, there is no frostbite! In the summer, it seems that it slightly cools the "fresh air"... just like the rear center vent. However, I haven't noticed the buttons effecting the rear air at all...
Rob
Note: Germans love their "fresh" air!
Rob
Note: Germans love their "fresh" air!
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merc s320 w140
this is how mine works
when you have the air con on running at low temp press the blue button you will get the cooled air from the front vents making sure you press the manual air distribution buttons left or right side so that the arrow faces the face is in black and the vent wheels are in the open position. only time you will get only outside fresh air is if the EC button is on lights up red as this will turn off the air conditioning compresser saving fuel hence EC is for economy. dont leave this setting on all the time or the seals in the compresser dryout crack and leak out your ac gas! the AC compresser gives out dehumidified air even when you put the temp on high that is when you select the red button for heated dehumidified air or normal heated air with the EC iluminated. hope that made sense! by the way the rear vents are fresh air only unless you have rear climate control wheels as an optional extra! cheers andy
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From: Twin Cities, MN
1999 S320 LWB
Ohhhhh! That's normal?! I was wondering about that...I thought mine was broken. Because I can never direct air to come out just from the dash vents, even if I push either the red or blue buttons. For example, it'll blow out of the dash vents and the defrost, or floor vents, or all three, but never just the dash. Unless it's warm out...then it'll blow out just the dash vents. Interesting...
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From: Houston, TX
02 S55
by the way the rear vents are fresh air only unless you have rear climate control wheels as an optional extra!
Regardless of the state of the cc (heating or cooling), the red/blue buttons open the cabin to outside air. I think the feature is there as another poster indicated - to allow some cool outside air into the cabin when the heated air gets stuffy.
From the owner's manual, the red button is called "Heated air supply button center air outlet" - the blue button is called "Non-heated/cooled air supply button - center outlet"
Usage instructions say: "With the center air outlets open and the system in heating mode, switch the outlets to non-heated/cooled air by pressing the blue button (indicator lamp lights up). With the center air outlets open and the system in cooling mode, switch the outlets to non-heated/fresh air by pressing the red button (indicator lamp lights up).
My experience is that when the cc is in heating mode, pressing the red button gives me heated air through the center vents. Pressing the blue button gives me outside air (non-heated). When the cc is in cooling mode, I never press the red button (why would I want heated air when the a/c is running?), but the blue button will duct outside air (which here in Houston means heated air).
Either way, the buttons bypass the cc and provide outside air, possibly adding heat to the airstream depending on which button is pressed.
For the rear passenger compartment outlet (without cc in rear) the owner's manual description says "Slide switch up to open outlet for fresh/cooled air only."
Just my experience - other's may vary.
