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Hi everyone this is driving me insane. On my 2002 E320 when I turn on the climate control there is a loud squeal most of the time. It happens more often when the climate control temperature is set higher than the ambient temperature. It never happens when the climate control is set to off. Before it starts making sound I can hear what sounds like an air channel or some part closing. I have replaced the blower motor and regulator two times with known working parts and the sound remains unchanged. I have disconnected the blower motor and the sound remains. I have uploaded a video on YouTube of the noise. The address of that video is:
The car has 160,xxx miles. I have searched for hours and hours and spent a lot of money on parts to no avail. Please help.
 

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i figured it out...

To anyone having the same problem, I figured it out. The noise is coming from a vacuum actuator, one of several which open and close flaps to divert airflow. To find out which actuator is making sound, I ran a flap test by holding down REST and recirculate simultaneously on the climate control unit. Pressing the left AUTO changes which flap to test and pressing the right AUTO closes or opens each flap (displays LO and HI). 0 is all flaps and in the first attached image is a list of the 15 flaps that are tested. There is another chart floating around that has incorrect information. This one seems correct. I head noise on 0-HI, 14-HI, and 15-HI. Looking at the chart the obvious culprit was the actuator for the right footwell flap. I peaked around looking for vacuum lines the same colors as the chart and found the actuator. My second attached picture is of that actuator after I pulled it out. My third picture is of where that is located, to the left under the glove box. That was where the sound was coming from. I ordered a new part, Behr 2028000275, about $75. Not bad. After months of annoyance and days of research I will (hopefully) finally have this fixed. Yay!
 

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After hearing your YouTube vid, the term I might use to describe the sound would be whistle.
Then seeing your fan "out" eliminated that and any air mass generated noise.
The fact of higher temp selection would not rule out a noise from the expansion valve, but in vid the noise seems too loud to be ex-valve.
I would by all means try Mrjarrod test of the flaps, I think he is 100% right in his diagnostics.
That said I am glad Mrjarrod helped solve Mrjarrod's problem, it's great when members help each other.
 

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i figured it out...

To anyone having the same problem, I figured it out. The noise is coming from a vacuum actuator, one of several which open and close flaps to divert airflow. To find out which actuator is making sound, I ran a flap test by holding down REST and recirculate simultaneously on the climate control unit. Pressing the left AUTO changes which flap to test and pressing the right AUTO closes or opens each flap (displays LO and HI). 0 is all flaps and in the first attached image is a list of the 15 flaps that are tested. There is another chart floating around that has incorrect information. This one seems correct. I head noise on 0-HI, 14-HI, and 15-HI. Looking at the chart the obvious culprit was the actuator for the right footwell flap. I peaked around looking for vacuum lines the same colors as the chart and found the actuator. My second attached picture is of that actuator after I pulled it out. My third picture is of where that is located, to the left under the glove box. That was where the sound was coming from. I ordered a new part, Behr 2028000275, about $75. Not bad. After months of annoyance and days of research I will (hopefully) finally have this fixed. Yay!
Mrjarrod, Bought a 2002 e320 couple weeks ago and it acts and sounds just as you described in your YouTube post. In coming here and seeing your photos I decided to give it a try. I have taken out some things that are in the way and can see the actuator but don't see how you can get it out of there and install a new one at the point where I am now at. I visited a MB shop today for transmission service and asked the owner about the actuator squeal. He smiled and said that's probably why the guy sold it to you because you have to remove the entire dash to get to it and said it is a 15 hour job. Did you manage to find a short cut to that, I hope? I may have to learn to live with it down in the sunshine state. Would appreciate an easier method to do this if you can give it to me. Thanks
 

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Anybody have a good idea on how to remove old actuator and install new one?
Welcome Nick, :)

There is a good video posted on the W163 forum by demoder that can give you some tips to follow for you W210
(of course, you need to watch some of the w210 videos explaining de-construction steps...)
 

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Welcome Nick, :)

There is a good video posted on the W163 forum by demoder that can give you some tips to follow for you W210
(of course, you need to watch some of the w210 videos explaining de-construction steps...)
Think that answers most of my questions Khomer2, thanks a bunch.
 
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