SL/R230: buzzing noise- climate control area
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Senior Member
Joined: Apr 2007
Posts: 436
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Former R230, W220 and W221 owner
buzzing noise- climate control area
2003 sl500
jumped in the car, and without starting it, i could hear a buzzing noise coming from behind the climate control area. Is there a fan back there? I see some vents in the climate control area- thinking of blowing some compressed air in there but wanted to confirm noise
It went away after I started the car and turned the fan on/off
jumped in the car, and without starting it, i could hear a buzzing noise coming from behind the climate control area. Is there a fan back there? I see some vents in the climate control area- thinking of blowing some compressed air in there but wanted to confirm noise
It went away after I started the car and turned the fan on/off
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From: Netherlands
2005 R 230 SL350 (M112 3.7). Sold the 1966 W113 230SL recently
‘Without starting it’ could possibly mean the car was woken up by either keyless entry or by having the key in the ignition.
If that was your situation I can imagine three sources:
1- the cc unit has a tiny internal fan with a temp sensor, which continuously sucks in cabin air for temperature measurement. Perhaps it is dependent of the open/closed status of the roof, because a similar unit sits near the rear vision mirror, which temp data is used only with the roof closed. (Both sit behind the small grilles we know so well).
2- the Comand unit has a fan
3- it seems that on hot days the chair ventilation is activated as soon as the car is woken up.
who knows..
If that was your situation I can imagine three sources:
1- the cc unit has a tiny internal fan with a temp sensor, which continuously sucks in cabin air for temperature measurement. Perhaps it is dependent of the open/closed status of the roof, because a similar unit sits near the rear vision mirror, which temp data is used only with the roof closed. (Both sit behind the small grilles we know so well).
2- the Comand unit has a fan
3- it seems that on hot days the chair ventilation is activated as soon as the car is woken up.
who knows..
Last edited by Frederick NL; Aug 27, 2020 at 01:50 PM.
Thread Starter
Senior Member
Joined: Apr 2007
Posts: 436
Likes: 79
Former R230, W220 and W221 owner
‘Without starting it’ could possibly mean the car was woken up by either keyless entry or by having the key in the ignition.
If that was your situation I can imagine three sources:
1- the cc unit has a tiny internal fan with a temp sensor, which continuously sucks in cabin air for temperature measurement. Perhaps it is dependent of the open/closed status of the roof, because a similar unit sits near the rear vision mirror, which temp data is used only with the roof closed. (Both sit behind the small grilles we know so well).
2- the Comand unit has a fan
3- it seems that on hot days the chair ventilation is activated as soon as the car is woken up.
who knows..
If that was your situation I can imagine three sources:
1- the cc unit has a tiny internal fan with a temp sensor, which continuously sucks in cabin air for temperature measurement. Perhaps it is dependent of the open/closed status of the roof, because a similar unit sits near the rear vision mirror, which temp data is used only with the roof closed. (Both sit behind the small grilles we know so well).
2- the Comand unit has a fan
3- it seems that on hot days the chair ventilation is activated as soon as the car is woken up.
who knows..
The car is in the shop- Indy said if he hears it, he will investigate. Bad thing is, if it is the vision mirror, the whole unit needs to be replaced- can't replace just the fan...smh
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Joined: Mar 2018
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From: Netherlands
2005 R 230 SL350 (M112 3.7). Sold the 1966 W113 230SL recently
Seeing the fragility of it all, I recommend not to hold a vacuum cleaner against the grilles and cause a tornado in there. You’ll surely break or at least dislocate the thermistor.
MBWorld Fanatic!
Joined: Mar 2018
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From: Netherlands
2005 R 230 SL350 (M112 3.7). Sold the 1966 W113 230SL recently
Squirrel cage fan, perhaps 15mm in diameter.
Thermistor (temp sensor) which lurks inside fan cage. That match is standard, not king size.
Thread Starter
Senior Member
Joined: Apr 2007
Posts: 436
Likes: 79
Former R230, W220 and W221 owner
But you can repair the fan. I did. It’s all very small (and dusty) but quite simple, squirrel cage type of fan. Perhaps it’s just scraping dust. To be more precise: had to re-solder the temp sensor, which sits inside the fan cage.
Seeing the fragility of it all, I recommend not to hold a vacuum cleaner against the grilles and cause a tornado in there. You’ll surely break or at least dislocate the thermistor.
Seeing the fragility of it all, I recommend not to hold a vacuum cleaner against the grilles and cause a tornado in there. You’ll surely break or at least dislocate the thermistor.
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Hi! Did you ever located the source of the buzzing sound from the climate controls area?
I have the same thing, the buzzing sound, likely from some type of fan is my guess, is coming from right behind the climate controls. I hear it when I enter the car and continue to hear it for a few minutes when initially driving the car. And then it goes away. After I park the car and stop the engine, even with the keys removed, can still hear it for a minute or two, and then it stops by itself.
Weird!
Thanks!
I have the same thing, the buzzing sound, likely from some type of fan is my guess, is coming from right behind the climate controls. I hear it when I enter the car and continue to hear it for a few minutes when initially driving the car. And then it goes away. After I park the car and stop the engine, even with the keys removed, can still hear it for a minute or two, and then it stops by itself.
Weird!
Thanks!
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MBWorld Fanatic!
Joined: Mar 2018
Posts: 1,442
Likes: 260
From: Netherlands
2005 R 230 SL350 (M112 3.7). Sold the 1966 W113 230SL recently
Yes. The fan keeps working for a while after you pull the key (or similar with keyless). The idea is that the climate control remains on the ball, in case you make a short stop. I guess you just don't hear the fan(s) with the engine running, of course they're supposed to run all the time.
A non issue, or I would be very mistaken.
A non issue, or I would be very mistaken.
Last edited by Frederick NL; Aug 11, 2021 at 02:34 AM.
Junior Member
Joined: Feb 2005
Posts: 36
Likes: 6
Yes. The fan keeps working for a while after you pull the key (or similar with keyless). The idea is that the climate control remains on the ball, in case you make a short stop. I guess you just don't hear the fan(s) with the engine running, of course they're supposed to run all the time.
A non issue, or I would be very mistaken.
A non issue, or I would be very mistaken.
Thanks for the reply! Yeah I hear the fan noise even when driving in my parking garage with the AC on low and no music playing. I'll try to see if I hear it after a few minutes after start up when I drive around town. I don't recall hearing it, but maybe you are right with engine running I stop paying attention to it.
If the sound of this fan something that can be silenced a bit or can't do much about it? I plan to take the console apart so I can remove the comand head unit to replace the dim and scratched LCD screen. Wondering when the console out and turned 90 degrees if there is something simple I can do. If not then it's ok. And this fan is inside the AC controls module?
Thank you!
MBWorld Fanatic!
Joined: Mar 2018
Posts: 1,442
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From: Netherlands
2005 R 230 SL350 (M112 3.7). Sold the 1966 W113 230SL recently
The photo's I posted above in #7 are from the overhead panel. There's a similar setup in the AC control unit. The two buddies supply interior temperature info to the climate control system.
Last edited by Frederick NL; Aug 11, 2021 at 09:12 AM.
