W220 air con question

[rutland-boy]

Hi,

about two months ago i noticed that the (what I call) fan in the engine bay seemed to be on quite a lot.

during a service (mb) I mentioned it to the mechanic and was told all was well, no faults etc.

It now seems, that it is connected with the aircon, if I turn the aircon off (ie press the switch to do so on the console so the display reads o), the noise after a few seconds slowly dies to nothing.

I assume that this is something to do with the air con compressor / fan ?

The air con has been re-gassed, no leaks, and other than this annoying noise the a/c works well.

Having read through some posts on this great forum it would seem that this might be a fan controller problem (?), perhaps 'water ingress', where is this controller ? and how can I check if its got water in it ?

Another post seems to suggest checking a relay, but where and which once ?

again sorry for the questions if they have been asked before.

Thanks in anticipation.

 

[television]

It would appear that a sensor is S/C I will have a look,,no promises

 

[rutland-boy]

as ever , thanks for any help possible...

 

[RivvaRoom]

I have exactly the same problem on my 2001 S500. I foolishly decided to wash the engine bay very carefully last weekend and since then then, the air con sounds like a jet engine on take-off. The air con and heater work absolutely fine and when you turn them off, the sound dies out but the noise is very annoying in low speed driving. It is obviously definitely due to water ingress somewhere under the bonnet. Is there anything I can do to dry something or another out? Any help greatly appreciated!!

 

[Cole@MBS]

Check the air-box on the n/s, ac inlet, the drain at the bottom blocks and may need cleaning out!

 

[rutland-boy]

Thanks will try that, sorry to be a pain but what does this box for a/c inlet look like ?

I had a quick look and couldn't find anything, although it is getting dark !

 

[television]

Open the bonnet and remove the grill in front of the windscreen, that is the air intake box and has drains in the bottom

http://www.detali.ru/cat/oem_mb2.as...GA=722.618&CT=F&cat=66H&SID=83&SGR=110&SGN=02

 

[rutland-boy]

Thanks I will try that and see if it helps.

I was tried (by an expert) that the fan controller (?) was faulty although no test by MB picked this up, so looking for any other answers.


Interesting that RivvaRoom has a similar problem perhaps a more general problem that I had imagined

Thanks for your help.

 

[television]

The component that can fail is the regulator, this is a semiconductor on these cars,when blown it normally leaves the fan in the slowest setting

 

[rutland-boy]

The component that can fail is the regulator, this is a semiconductor on these cars,when blown it normally leaves the fan in the slowest setting

Would this give the problem that I have ? , the fan (whichever one it is!), seems to be on all the time, and as RivvaRoom says at low road speeds its annoying, to say the least.

I can stop it by turning the aircon off (0), the aircon / heater etc is working fine and has been recharged and given a clean bill of health from an aircon tech.

If this is the part, can I change it or is it an MB only job ? I'm pretty handy with cars / electrics etc. Do these parts go pretty regularly (as RivvaRoom possibly has the same problem) ?

Thanks - Chris.

 

[television]

http://www.detali.ru/cat/oem_mb2.as...GA=722.618&CT=F&cat=66H&SID=83&SGR=045&SGN=01

350 in the link.


If you can speed the fan up via the control unit it may not be the regulator, but it could leak,via an internal short. they are not cheap at £150,, but often on Ebay

 

[rutland-boy]

I have now checked the drain hole and .... no change they were not blocked

So any other ideas ? Having had the bonner open its definitely the fan (or one of the fans in the radiator area (sorry for the poor description), It does not seem to be the 'proper' radiator fan as this comes on a off as the car warms up / down which seems normal.

It is defintely something with the aircon, as when I switch the aircon off (zero on the control panel) it stops the 'other' fan running.

Any more ideas ? perhaps this is one for MB or a MB specialist sparks ?

 

[television]

OK the engine /rad fans are for use with air con, and they can run on,when the engine is off

We had another member joining the thread and that has confused it a little as he was talking cabin fan.

If one of the rad fans is running all of the time, it should just be a short circuit sensor, or possibly a SAM fault

 

[rodbromiley]

W220 Air Con Re-Set

Can anyone help or advise.
Had W220 RE Gassed but EC light remains ON

On here it says that you HAVE to re-set Computer, HOW do I do this ?

 

[lennartephraim]

1. Push charcoal filter button and REST at the same time (about 5 seconds)
2. you can scroll to see the fault codes
3. to delete the fault press the left air AUTO button and then press the right air AUTO button.

Ensure that the freon level was the only problem, because the computer does not turn off A/C for no reason. However, fault delete would cost you around $30 at MB-dealer.

Hope this helps.

 

[Myros]

thanks Lennartphraim

that routine of yours saved me $30. and got my aircon going again.