Weird Buzzing/Whirring Sound - In Sunroof Motor/Interior Lig

[StewartS]

Whenever the ignition is on in my 1996 C200 there is now a buzzing or whirring sound from behind the interior light / sunroof switch in the sunroof motor area.  It is definitely a high speed whirring/rotary type sound as when I turn the ignition off I can hear the whirring slowing down to a stop.  Is the sunroof motor the only  'rotary motor' in that area - are there any more motors above the interior light/mirror fittings? Is there anything in that area which should be spinning while the ignition is on? Does the sunroof motor always turn? The sunroof works OK.,but this noise has just started and is really annoying in an otherwise quiet car. Any advice appreciated. Before I investigate a pretty inaccessible area I'm keen to know what I'm looking for.

 

[David Halsey]

Weird Buzzing/Whirring Sound

As far as I am aware there is no other moving part there.
bit of a puzzler!
There is a relay built into the interior light unit, it controls the delay between closing the door and the light going off, as a bit of a long shot this may be causing the problem

 

[Anonymous]

Weird Buzzing/Whirring Sound

Could be - it sounds weird - Car booked into Rycroft at Stockton on Thursday to see what they can make of it - It's still got 6 months of a Signature warranty left on it, so should be covered ( I Hope )

Stewart

 

[Stewart Smith]

Weird Buzzing/Whirring Sound

Update. Dropped the beast off at garage.   Very helpful service guy at Rycroft (well done Rycroft - thats one up on the joke that is customer service at Leadleys in York ) says it might be the tiny fan on an interior temperature sensor which is located behind the interior light/rear view mirror area.  Sound familiar to anyone?

 

[Hollo]

Weird Buzzing/Whirring Sound

Just to confirm what Stewart has said ( don't worry you are not going mad ) , I get the same thing , sometimes when I get into my 1989 230TE  , there is a slight whirrring noise , and after reading this post the next time it happened I didn't turn the ignition on and waited for the interior lights to out.........but the noise stayed on , I got bored after a couple of minutes . Obviously its not a major fault but at the back of mind I wonder how long the noise could be going on for and if it could eventually drain the battery ?

Mike .

 

[StewartS]

Weird Buzzing/Whirring Sound

The culprit has been identified!  - It's an interior temperature sensor hiddedn above the rear view mirror which has a little fan to draw the air through it.  £45 plus fitting - but none in stock and none in Merc UK apparrently - so I'm waiting for one being ordered in.  All under the Signature warranty though.

 

[StewartS]

Weird Buzzing/Whirring Sound

Must be my luck.

(Edited by StewartS at 8:30 pm on Jan. 17, 2002)