Ventilation not working - NOW REPAIRED!

Shude

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Ventilation not working.

No matter what I do with the dials, there is no movement of air.

Anyone got any clever ideas?

I checked all the fuses, they're fine. I took the dashboard apart to make sure the plug in the back of the unit is firmly seated, it is. At about 70mph there is a small amount of moving air, the temperature is whatever the dials are set to. All the buttons work (I can hear stuff when I press them). When I turn the key before starting the car, I can hear something whirring in the engine bay, but it sounds like it's starting and stopping, on, off, on, off. Could this be the aircon compressor or something?

I get the feeling that ALL the gas has escaped from my aircon system and without ANY of it being there a sensor has told something not to work as a failsafe so it won't damage itself. If this is the case then I will clearly have to get my aircon repaired.

Any ideas would be appreciated :)
 

Steve_Perry

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Nick,

If your a/c had auto switched off due to lack of gas the 'EC' (economy) light would be on permanently and could not be extinguished with button pushing.

You also state "the temperature is whatever the dials are set to" again if you had a gas leak this would not be the case, you air would come out warm or at best outside ambient temperature but never cold.

Is the problem a lack of air volume flow? or air routing not behaving as you would expect?

If it's the former, what happens when you turn the fan speed setting up?

If it's the latter, I'd also check the mechanical linkages from the dash side plugs (i.e where the a/c module's mechanical plastic pins plug into) You say the module plugs in firmly but what if what it plugs into has lost it's link in the chain?

S.
 

jimmy

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I recently had the same with mine but it was intermittent, sometimes the fan would work and sometimes it wouldnt. Try banging the trim under the glovebox where the fan is, if the fan starts then you have a faulty fan like me.

I removed the fan, removed the carbon brushes and cleaned them with a piece of sandpaper, cleaned the whole motor with brake cleaner and replaced it. It now works fine but I am getting a new fan under warranty, about £130.

You could try squirting a drop of WD40 onto the bottom of the motor where the brushes are and see if that gets it going. According to MB it is a common problem for the fans to fail.

I thought it was my SAM unit causing the problem so I ordered a new one from the stealer 5 weeks ago and they are still waiting for it to arrive from Germany! Unbelievable.:confused:
 
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Shude

Shude

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Originally posted by Steve_Perry
If your a/c had auto switched off due to lack of gas the 'EC' (economy) light would be on permanently and could not be extinguished with button pushing.
I wondered that too, that's not happening.
Originally posted by Steve_Perry
You also state "the temperature is whatever the dials are set to" again if you had a gas leak this would not be the case, you air would come out warm or at best outside ambient temperature but never cold.
It is never freezing, but it is cold.
Originally posted by Steve_Perry
Is the problem a lack of air volume flow? or air routing not behaving as you would expect?
There is no air flowing at all, everything is turned on but the speed is less than you'd expect for a setting of "1" and there is no fan noise at all.
Originally posted by Steve_Perry
If it's the former, what happens when you turn the fan speed setting up?
Nothing happens no matter what fan speed is selected.
Originally posted by Steve_Perry
If it's the latter, I'd also check the mechanical linkages from the dash side plugs (i.e where the a/c module's mechanical plastic pins plug into) You say the module plugs in firmly but what if what it plugs into has lost it's link in the chain?
The mechanical linkages ONLY control which vents open and close, I experimented with this today, they do nothing to the speed of the fan. I have no idea where those cables go to, they vanish through a hole into the engine bay.
Originally posted by jimmy
I recently had the same with mine but it was intermittent, sometimes the fan would work and sometimes it wouldnt. Try banging the trim under the glovebox where the fan is, if the fan starts then you have a faulty fan like me.
It has worked intermittently I think, sometimes it would blow very well and I thought it was my imagination, but it's completely dead now :(
Originally posted by jimmy
I removed the fan, removed the carbon brushes and cleaned them with a piece of sandpaper, cleaned the whole motor with brake cleaner and replaced it. It now works fine but I am getting a new fan under warranty, about £130.
I have no warranty to fall back on, so this is coming out of my pocket! Where is this fan? I took the cover off the underside of the glovebox and also removed the glovebox liner, couldn't see anything except a bunch of pipes, is it inside one of the pipes? Got any pics?
Originally posted by jimmy
You could try squirting a drop of WD40 onto the bottom of the motor where the brushes are and see if that gets it going. According to MB it is a common problem for the fans to fail.
I think I will get a quote for a fan from a breaker, assuming it is definitely the fan that's gone, hopefully won't be too expensive.
Originally posted by jimmy
I thought it was my SAM unit causing the problem so I ordered a new one from the stealer 5 weeks ago and they are still waiting for it to arrive from Germany! Unbelievable.:confused:
What is the SAM unit? Sounds expensive! :(

Thanks for all your help chaps, maybe I might be able to get this fixed soon! My windows don't de-mist any more so it's becoming a nightmare! :(
 

joe

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Have you checked your Pollen Filter?
When blocked, this will prevent any air changes/air movement.

I found a few other posts

Link

Joe
 

Alps

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Shude,

try the pollen filter first!

my heating also has started playing up, only get hot air coming thro whatever temp i have the settings at! mechanic says its something called the "dynovalve" it apparently collapses and only hot air comes thro!

can anyone comfirm this? the part is over £300 from a stealers apparently.

:(
 
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Shude

Shude

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I'm going to pull that pesky pollen filter out soon, it looks like it's under the glovebox so shouldn't take more than a few minutes to do :)
 
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Shude

Shude

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ok the pollenfilter is out.

With it out the ventilation still has zero air movement at full speed (also no sound).
 

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jaymanek

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Id find the fan and makesure theres power going to it, then go from there.

P.s You dont keep your history etc in that wallet in your footwell do you?? Every thiefs dream to have all the paperwork aswell as a nicely modded motor!
 

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The fan is next to the pollen filter, to the left. There is a cover with two sliding clips at the front, remove the wire and the clips then there are 4 torx screws to remove the fan motor assembly.

First remove the cover, spray a drop of wd40 onto the bottom of the motor where the carbon brushes are and with the fan switched on use something plastic and flexible like a straw to give the motor a nudge. If the motor starts and runs it is worth taking it out and giving it a good clean. Mine is working fine now after three weeks of doing this, but the brushes are worn so I thought I may aswell get a new one under warranty.

Oh, if you do remove it and clean the brushes make sure you clean it well with meths or brake cleaner and do not leave WD40 on it, it will smell and make the motor sticky again.
 

Dieselman

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Originally posted by Alps
Shude,

try the pollen filter first!

my heating also has started playing up, only get hot air coming thro whatever temp i have the settings at! mechanic says its something called the "dynovalve" it apparently collapses and only hot air comes thro!

can anyone comfirm this? the part is over £300 from a stealers apparently.

:(

Not sure on the price but the problem could well be the duovalve. The diapragms inside can split allowing hot water through all the time. Not sure but I thought the diaphragms are available from the dealers.

Before condemning the valve you need to measure the voltage across them. It should be 12v or thereabouts in one state and 0v in the other, not sure which but I think 12v closes the valve, so if there is no feed you will roast!
 

Dieselman

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Shude

I agree with Jimmy. Your fan is not starting and stuck / worn brushes is common.
It could be the fan speed control board, which may have dry solder joints, or in your case it could be the connection to the dashboard fan switch given your love of dash removal.
 
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Shude

Shude

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Originally posted by Dieselman
I agree with Jimmy. Your fan is not starting and stuck / worn brushes is common.
Fan is coming out tomorrow for an inspection.
Originally posted by Dieselman
It could be the fan speed control board, which may have dry solder joints, or in your case it could be the connection to the dashboard fan switch given your love of dash removal.
If you've ever seen the connector that goes into the back of the control box on the dash you'll know it's not a "bad connection" there, it's a huge plug with a plastic arm that using a little gear clamps into the back of the control box. A little Heath Robinson but it's not going to fall out ;) . All the other buttons and dials work so I'm assuming that end of it is working fine. Air re-circulation, aircon, heated rear window, air temperature and "rest" still function correctly.
 
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Shude

Shude

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Originally posted by Shude
Fan is coming out tomorrow for an inspection.
Looks pretty stupid doesn't it?
 

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Steve_Perry

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Originally posted by Shude
Looks pretty stupid doesn't it?
I've seen worse, main thing is... does it work?

S.
 
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Shude

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Originally posted by Steve_Perry
main thing is... does it work?
Not as far as I can tell. I just gave it 12v and it did nothing. :(
 

Steve_Perry

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Originally posted by Shude
Not as far as I can tell. I just gave it 12v and it did nothing. :(
Bummer :( Does the motor look like it's integrated into the fan unit or does it look like a separate bolt on part? You maybe able to get a replacement motor without having to get robbed for a whole fan unit. Wouldn't be oem though.

S.
 

Aswall

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Visions of Shude "upgrading" the motor with one off a hoover or a Flymo to give better performance :D

Cheers
Andy
 
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Shude

Shude

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Originally posted by Aswall
Visions of Shude "upgrading" the motor with one off a hoover or a Flymo to give better performance :D
That motor takes a 30 amp fuse, it's a serious piece of kit!

I got some prices today, £165 retail from the parts dept, £65 from a local breaker (Dronsfields). The parts dept have offered it for £135 inclusive, it's still expensive but it's brand new. The second hand one from Dronsfields comes with a 3 month warranty, but they won't know if it's any good or not and they said they only have 1 in stock - if it blows up next week it's doubtful they could replace it easily and I would be without ventilation again - it would be from another c-class and could be just as worn as the one I have already. I'm thinking maybe new is the best option...
 

Steve_Perry

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Originally posted by Shude
...if it blows up next week it's doubtful they could replace it easily and I would be without ventilation again - it would be from another c-class and could be just as worn as the one I have already. I'm thinking maybe new is the best option...
In this case I would plump for brand new as it's a part that's spinning/moving for most of a car's life. 18% discount? that's a cool gesture from the parts dept. I take it that no amount of oiling, cleaning carbon bushes etc, coaxed the old one back into life?

S.
 

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