lukas.smrcka

Hi everyone,
I have 4 months old MB GLE 300d that is suffering with a weird issue. When it is hot outside (30 C or 86 F or more) and I drive usually longer time then 45 minutes then some servo most likely in ventilation goes crazy a starts continually making the sound in the attachment. The sound is there non stop and it is going on continually. I have observed that the sound stops when the temperature outside goes down (when I was driving over night it stopped after 3 hours). Today I tried authorized service of MB (In Czechia) and the result was they couldn't see anything in logs or diagnostic and they were not able to reproduce it so I can't apply warranty. The video was not enough because they didn't get any error code when doing diagnostics. Their message was I should come when it starts happening, but conditions to reproduce it are complicated ... Guess of my dealer from Germany was that the issue is servo for ventilation control and it most likely needs to be reprogrammed however I don't want to go to Germany just to get this thing fixed and with uncertain result ...
My question are following:

• Any idea what could be the problem and what could help to reproduce the issue in the car service?
• Any idea how to disable it (or bypass it) when driving? None of air conditioner controls helped to control or affect it somehow. And it is super annoying when driving and listening to this sound for hours, it is also very disturbing.

I am sending the audio record of the weird sound in attachment and image with marked area where the sound comes from.

Thanks for any ideas,
Lukas

CaliBenzDriver

You won't go very far without interrogating the car computers with a scanner.

The mp3 noise sounds lighther than would be the cabin blower.
I guess it is one of the 5+ flap actuators unable to reach target position
-or the AAC controller unable to acquire feedback signal... scan to save ressources

lukas.smrcka

Agree ... not the cabin blower. The air flow was always ok when this was happening
What is AAC controller? You mean Air Conditioner controller?

Yesterday I tried to play with manual setting of the air conditioner/ventilation switching it to all types of "air distribution/directions" (to windscreen, torso, feet). None of that made a sound that would be at least reminding the weird sound from the attachment.
Is there any way how to check those flaps if they aren't blocked by something physically (like a big bug or something )? Are these flaps in ventilation or where are they?

About the " interrogating the car computers with a scanner" ... the issue is nothing is visible in logs and my car service does not want to do anything without reproducing the issue ... and they are not able to reproduce it. So quite frustrating. After tomorrow it should be really hot here so I will be probably driving circles around the city to reproduce it and then directly to the car service on diagnostics ...

CaliBenzDriver

there are so many devices on these cars, it's not trivial to know which one is acting up! I don't think it's fair to fet idiotic service on a new car. The proper attitude would be to make the ownership experience not suck.

Does the noise stops when you set the HVAC to OFF?
I am going to guess yes....:
From here there are not too many MOVING PARTS than can produce that sound... so far I am guessing flap actuators. They are responsible for moving HVAC flap doors into positions. The Blend door is a busy one to adjust output temp. It's new, it should not be broken so soon.

Get your own scanner to get data on tap!

lukas.smrcka

"Does the noise stops when you set the HVAC to OFF?" ... When I experienced the issue I was manipulating with HVAC using phisical buttons without much focus because I was driving. I tried a lot of circulation combinations ,heating, cooling but I can't confirm it was fully off. Now I know how exactly it looks like when it is turned off ... so I am going to try next time when the issue happens

When it started there were only two situations when it stopped. I finished my ride and left the car or the outer temperature dropped at night. The temperature drop case was basically a ride that started 10PM .... it started 10:30 or so .... it stopped around 1AM and hadn't started again, I was driving whole night until morning. So that's why I guess temperature affected that.

The blend door idea - I haven't notice any weird behavior of the air flow or temperature inside. But haven't checked state around back seats ... maybe I can try.

The flap actuator idea - yes it sounds like an actuator. And as you mentioned it is failing to reach desired position

Getting the scanner - ok when I become desperate person then it would be an option but I guess it is quite expensive toy. For now I am more focused on reproducing it and then getting it to the service

Anyway thanks for ideas, that's actually what I would expect also from my service