Air Vent Speed not consistent... flow changes under electrical load

Aug 27, 2013 | 10:36 AM

Rambino951

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Air Vent Speed not consistent... flow changes under electrical load

I noticed on my w211 E Class and W219 CLS, that the air when blowing medium or hard, it never flows consistently.. If Im in neutral and a give it a small rev, its almost like it causes an electrical load and the fans speed up and then slow down for a second.. This also happens when I fumble with the electronics..

It kinda annoys me when I constantly hear the fan speed changing when I slow to light, or mess around in the cabin.. Its not a major change, but its not consistent.. Its not trying to adjust climate control in the car, its clearly something to do with electrical load and the air coming from the vents slowing momentarily and then resuming..

Has anyone else noticed this?

I was gonna take some sandpaper and strip down all the Ground connections around the car I can find to see if that helps..

Aug 27, 2013 | 11:53 AM

MAN55LE

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Joined: Mar 2013

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From: America

04 E55 AMG

my fan is inconsistent also, would love to know what it is, also sometimes i hear a little bird coming from the fan....and it is not my sc engaging....any thoughts

Aug 27, 2013 | 12:30 PM

shardul

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From: Houston

2003 W211 E55, 2003 W220 S600

Some MB models have issues with the final stage regulator.

Aug 29, 2013 | 07:45 PM

Rambino951

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Nah its not a regulator and the birdie you hear coming from the fan is the open/close manual setting on the vents, just adjust them all to full open or play around with it and the birdie will stop..

I think its just the load on the alternator fluxuating when other electronics are being used or the engine revs it up.. really is a ****ty thing and for the ocd types like me it makes me crazy to constantly hear it speeding and slowing down ever so slightly.. Im going to file down the ground points around the car and hope that clears up some of the frequency and power interference.. The grounding kit I had on my old EVO really cleaned up the electronics signals and even made the car feel like it revd up a little more freely for some wierd reason..

Aug 29, 2013 | 07:56 PM

Ronan Mc Cabe

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From: ATL

Gone but not Forgotten 2006 E55 Renntech

Quote:

Originally Posted by MAN55LE

my fan is inconsistent also, would love to know what it is, also sometimes i hear a little bird coming from the fan....and it is not my sc engaging....any thoughts

The little bird could be your blower motor (sits under the dash passenger side), sometimes the chirping can be fixed with WD40, in my case I had the blower motor replaced & no more birdies

Sep 1, 2013 | 02:05 AM

MAN55LE

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Joined: Mar 2013

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From: America

04 E55 AMG

thanks for the input boys

Sep 1, 2013 | 09:22 AM

55fanatic

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From: Boston, MA

00 MB ML55, 91 Toyota Supra Turbo(sold), 06 E500(gone), 03 BMW M3

Could variable electronic performance signal an outgoing battery or alternator? Same symptom of a car with a crazy stereo and no capacitor... We have the second battery but if that is low due to age and failing performance or its low because there is a fault in the charging system, in theory could mean the same thing?