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C280 buzzing noise from roof switch cluster?

1998c280estate

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Joined
Oct 19, 2009
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14
Location
Bromley, Kent, UK.
Hi all. Here's a weird one. (I've searched the forum but can't find another example).

Every time I turn on the ignition to start the car (1998 C280 Estate, owned from new), there's a loud buzzing noise coming from the cluster of interior light switches on the roof/headlining. This has been going on for some months - I used to think it was just the heater fan, but now I see it's not. It's not noticable when the engine is running, so it may stop (unlikely). More likely it's still buzzing but inaudible over the sound of the engine. All the switches and lights work.

Any ideas what it is (I've ruled out bees)? Hope it's not an electrical switch buzzing itself into a fire... Any suggested fixes?

I see there's a small plastic grille up there, just in front of the mirror - is that part of the aircon/heater? Any moving parts?

Also, could this be linked to the tailgate interior light mysteriously coming on (and draining the battery) some weeks ago? Since then I've turned off the automatic interior lights coming on when the doors open, until I've checked the tailgate switch.

How do I prise the switch cluster off the headlining without damaging anything? (I broke a door handle cover getting it off to change the door capping, so am now very wary about how to prise plastic fittings apart without breaking them).

Many thanks!
Cheers,
John​
 
It's a little fan that draws in cabin air to measure its temperature for the climate control system.

I believe it's possible to get at it when the overhead console is removed, there's probably a ladybird in it.
 
Hi,
As Stratman says there is a small fan behind that grill that will be giving your buzzing noise.
To remove the overhead light panel remove the two interior light lenses and on the rear most edge of the panel you will see two clips, one either side push these clips towards the panel and lower the rear edge of panel down and pull towards you, then just disconnect the plugs, the fan is approx. 20mm square behind the grill you mentioned, you could try to lubricate the fan motor spindle, but i think you will end up replacing it.
I think the Pt. No. for the fan is A1408300008, your MB should confirm this.
 
How much is the fan ????????
 
It can also be the capacitor for the interior light discharging making the noise. All of my 202's that I have owned and one 210 have done it.
 
Thank you all! Sorry I missed the previous posts which covered this. Sorry also for the delay in replying - pc problems.
Cheers,
John
 

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