aomE500

Hello,

Well, as some of you may recall, I have an 05 E500 that's on order that I was about to consider cancelling because MB decided to remove the Top Center Vent Cooling Dial. This dial allowed you to adjust the top center vents (the ones on top of the A/C console) to keep a different "cooler" temperature from the other vents.

This way if you had the temp set to say, 83 degress, all the other vents would blow hot air, but you could control the top center vents so that it blew cooler air, thereby reducing the heat that would blow in your face, creating less fatigue/drowsiness. My BMWs had this and they were a great feature in the cold (they also heated too, but I digress since I never used THAT).

However, if you have the temp set to Max heat, or thereabout, the center vents WILL blow out hot air at the same temp as the others, thereby allowing for full heat (if it's particularly cold).

It seems like MB removed that dial, but keep the "feature," just simplifying it instead!

I'd like to thank "hlkc" for helping me find this out on his 05 E500, and sitting in his car for 5 minutes w/ hot air blowing, while on the phone w/ me no less!

I'm once again looking forward to delivery! (This is great too since I've resigned myself to accepting the new armrest console, not too bad in person actually, plus I think w/ Black leather and red burl wood, it will look great. I also heard about the REST button being removed, I can deal w/ that since I never really used it on my 540). I thought that the dial was the last straw, but it seems like technology is still there, so I can still bring that up and impress my friends!

hlkc

I am glad that I can help. Hope you will find a good deal and do keep us update.

Thanks!

BudC

I'm lost. If the original purpose of the large center vent on top of the dash was to provide some fresh air when you have the heater on, then what does it do now?

If it also blows hot air, what good does that do?

I have a 2004 E320 built in March of 2004. It has the dial for the large center vent but it appears not to be connected to anything.

I suppose if I didn't live in Arizona I would have used the heater and then I would have noticed if anything changed when the center dial was rotated. Since the dial is in blue I suppose that means cool air.

scorchie

There is some misconception about the large upper center vent in 2003/2004 US-spec cars, and the center control for "adding cold air". It does not work as the C-class version does.

On cars with either full or partial automatic climate control, the center dial does nothing when the climate control is set to automatic (which is where it almost always is on my car). "Only in manual mode is it possible to lower the temperature in the headroom by regulating the cold-airflow using thumbwheel (7)"

-s-

ATS

Yeah after reading these posts I put my hand there with the dial up and down and I couldn't feel a thing coming out of the vent.. Dissapointing..

jim256

Although it has been covered before, I'll point out that the effect of the blue wheel, even though you have properly put the system in manual mode, is not immediate. The wheel controls a switch which opens the vent. The C Class I had used a mechanical link to open the vent directly.

BudC

Is this in the manual? I don't see it in the one for my 2004 E320 (3/04 build).

HotWheels500

What did "hlkc" help you to find out? You say the feature is still there, but simplified. My top center dash diffuser vent appears to have no connection with the A/C. I believe it's a speaker, and that's all. Am I wrong?

aomE500

Hello,

Was talking about center VENTS that face the driver/passenger, not the center VENT that faces the windshield.

Hope that helps.

ATS

The center dial is only for the large top vent that was deleted on the 05's.

HotWheels500

So, is there any A/C related function to the large top vent in the 05s? And if so, is there any user actions to make it work?

BoSoxFan

I've been experimenting with this. It appears to me that the center vent with blue wheel is fed by 'ram air', air which is not supplied by a fan but from the motion of the car. I can't detect any air from that vent while the car is standing still, only when moving. As others have noted, there does seem to be a delay when the wheel is turned. I haven't noted any difference between the automatic climate control being on or off but perhaps I haven't experimented enough.

scorchie

On 2005 cars I believe the large top "vent" is just for the speaker.

-s-

HotWheels500

thanks scorchie. that's how it seems to me as well. nevertheless, the 4-zone A/C works quite well.