W203 c class - loud clicking noise

kingycos

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Apr 5, 2013
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mercedes cl600
My 2005 c class has developed a loud clicking nose behind the dash board every time it's started up. It lasts for about 10/30 seconds and then disappears. Can anyone shed any light on this for me please? The car drives perfect with no issues as normal. Any help is really appreciated
 

brucemillar

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A very common and very expensive problem = £900ish. It is a dashboard out job.

The blend flap (plastic) gears have broken. Each time you turn on the ignition the flaps will attempt to register their position by the gears turning. When they break! What you hear is that process as the gears now cannot register and the flaps are being driven over the broken teeth.

You could just leave alone, many do. The issue is the noise and the possibility that your heating/AC will not direct as you set it to. So you could (if unlucky) have freezing air blowing on your face all day. Also when you try to sell it....You guessed it. Whats that clicking sound I hear?
 

whitenemesis

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Depends which flap it is. One maybe two are accessible from underneath.

Get the codes read using STAR, to pinpoint the offending flap
 
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kingycos

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Apr 5, 2013
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mercedes cl600
Thanks for you help I've had a look today and it seams really low down so hopefully I won't have to take the dash out. Are all the flaps the same so when I order one from Mercedes I get the right one?
 

Tim203

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Sep 17, 2014
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brucemillar said:
A very common and very expensive problem = £900ish. It is a dashboard out job. The blend flap (plastic) gears have broken. Each time you turn on the ignition the flaps will attempt to register their position by the gears turning. When they break! What you hear is that process as the gears now cannot register and the flaps are being driven over the broken teeth. You could just leave alone, many do. The issue is the noise and the possibility that your heating/AC will not direct as you set it to. So you could (if unlucky) have freezing air blowing on your face all day. Also when you try to sell it....You guessed it. Whats that clicking sound I hear?
Sorry to crash the thread but top explanation Bruce .My203 has literally started doing this last week. I'm convinced Mercedes send out signals for these cars to fail. I'm lucky I have the forum and my own facilities to repair my car. I haven't noticed any difference to the heating system though. It's still rubbish !

Edit; mine sounds like someone's locked in and tapping to get out!
 
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