round circle on dash

[rom1]

There is a circle shaped grill/vent on the dash inline with indicator stalk.

Does anyone know what it is?

 

[NDFR]

Mic pick up?

 

[whitenemesis]

Cabin air temp sensor?

 

[LTD]

Alarm sensor ?

 

[paul73mt]

Cabin air temp sensor

 

[rom1]

Cabin air temp sensor thank you

http://www.mbclub.co.uk/forums/interior/158288-w204-mystery-grille.html

 

[thedruid]

I thought it was the mic. for when using hands free. I'll have to put my thumb over it when I next use hands free to satisfy my curiosity.

I'll let you know..

 

[thedruid]

Just tried it. Thumb over the grille, no difference in speech over the phone. Next question. Where is the hands free ( on bluetooth ) microphone?

 

[AMGeed]

That is in the overhead display to the right of the rear view mirror. (For a W211)

Apologies for the photo being on its side. It needs rotating to the right for the correct view

 

[MancMike]

It's definitely the cabin air temp sensor. There's a small fan which gently draws air into it, which is why they're usually a bit dusty. If it was a mic, it wouldn't pull in dust like they do.

I'm not sure but I think the mic is in the rear view mirror, there's some slots underneath it, and there's a device with wires coming from it pressed up against these slots on the inside of the mirror.

 

[markjay]

For the W203, there are definitely two type of mirrors, one with
internal mic and one without, so the mic is in the rear view mirror on at least some models.