2000 C280 high-pitched sound behind dash
 

Hi All,

This just started yesterday evening when I drove home:
A high pitched (about 10kHz or so) realtively loud sound started coming from (as far as I can tell) behind the air inlets in the middle of the dash. It gets louder for about 5 seconds, stays for 5 seconds and then fades out. It happens about every minute. It has nothing to do with my stereo - although the noise is as it would come from some speakers. Could it be the hands-free speakers for the integrated cell phone? Anybody?

Thanks,

Greg

noise
 

Could be a vacuum leak, but the one minute periodicity is a bit puzzling. If the sound disappears as long as you're on the cell phone I doubt it's the speakers for your cell. Vacuum leak sounds likely, I would think.

A/C system vacuum leak is the MOST likely.. does that happen in the heating & A/C mode...WHAT about in the EC mode.. THE fresh air door vacuum element is a constant problem on the 1994-2000 W202 chassis

My climate control was on Off.

what is the purpose of the fresh air door vacuum element and where is it located?

Thanks,

Greg

WITH the system off .... the fresh air vacuum element DOES have vacuum applied to close that door... that would be the NOISE...

is this an easy fix?

I too am interested if this is an easy fix? The same problem occurs with my '98 C230, the high pitch squeel only occurs when the climate control unit is OFF. But as soon as I turn the system ON, either with "EC" on or off, the sound disappears.

I've always suspected the blower motor is the main culprit, it does make a loud noise especially when it is 14 or below outside. Your help is appreciated!

About 2 months ago with the advent of cold temperature, a similar problem began when starting my 94 E320 after all night in the garage. An annoying squeal from behind the dash on the passenger side. Occurs with the climate control either on or off; continues about 10 minutes then stops. Annoying but I'll live withit until I replace my leaking A/C evaporator.
regards,
Mark

The fresh air door vacuum element takes a good MB tech about 4.5-5 hrs to install. The dash does have to be removed.

Well then i'll just keep my A/C on EC.

Any chance thaere is or was a recall on this?
 

I am really annoyed by that noise. Now it even happens every now and then if the fan is running on low. I have had my fair share of problems with the climate control (fading display that needed a disassembly, cleaning and tightening. I am not very happy with the quality of this car (I do not mean to start flame on this issue).

Anyway, is there any chance there was a recall or that one could be made as this seems to be a very common problem?

Thanks,

Greg

Mercedes, recall? HAHAHAHAHAHAHAHAHAHA!

Wow, gives a new meaning to hard llabor
I think I'd have to learn to live w the noise.