Help needed to resolve a problem.

[K.Rob]

I bought a Mercedes CD 220 in June 2015. It was an ex demonstrator with only 400 miles on it. It was 2015 registered on a 64 plate and 12 weeks old. It was brought up from another Mercedes Garage and I was very happy with it.
As I drove away I pulled up at traffic lights and could hear a fairly loud buzzing noise. I drove straight back and they booked it in saying they would fix it and it was in the overhead panel. When I picked it up as soon as I drove away it started again.
In short it's been in 4 times once for over two weeks had 2 new panels and some wiring re routed. It was quieter and the manager said they had opened a dialogue with Mercedes Berlin who told them that as it is a moving part I should expect some noise.
I was told that was the end of their involvement. The noise is louder now and when I pull up at lights or park up it is so annoying as the engine noise is not present. In my work I travel to places and take people out. They always comment on the buzzing noise.
The other day I was sat in the car and locked it with the sensors on. After around 3 minutes the buzzing noise switched off. As soon as I opened the doors it started again immediately.
I'm staring to get a bit stressed about it as I'm worried it will effect sell on or trade in. I would go back to the dealer but they make me feel I'm a nuisance very picky and basically say there's nothing they can do.
Sorry about the long post but I could do with some advice what to do next.

 

[fabes]

Where in the country are you?

Have you eliminated simple electrical issues one by one (lights, fan, climate, mobile Bluetooth etc)
Have you had the codes read via STAR system at a garage?

 

[K.Rob]

I haven't done anything as it's still under warranty.The main dealer has had it in 4 times for a couple of days each time and once for over 2 weeks.I think The sound comes from behind the dashboard they say it's the overhead control unit. They have replaced it twice but no good.
They seem to have given up on me.
I'm in Middlesbrough.

 

[Headhurts]

That sort of noise would drive me nuts and is certainly something I would make a fuss over.

If other CD220 do not make this noise then it's a fault and should be rectified under warranty.

Both my previous E300 and my present E350 make buzzing or motor type noises when locked/unlocked but they all cease after a very short period or when car is started.


Sent from my iPad using Tapatalk

 

[como]

Hi,
Is the Dealership Sytner Teeside? I only ask because I have used them for over 4 years now and they have been excellent. More importantly they seem very focused on their customer ratings with Mercedes. If so, a quick call to MB Customer Services might re focus their attention.

 

[Rory]

If other CD220 do not make this noise then it's a fault and should be rectified under warranty.

^ This. Have you tried another car to see if it's the same (or to point out to the dealer that it's not)?

It's a bit odd that the dealer is replacing the overhead console and you think the noise is coming from the dash.

 

[grober]

In some models I believe the overhead console contains an air circulation fan to blow cabin air over a sensor which forms part of the airconditioning unit. Not sure if this works continuously or at intervals controlled by the air conditioner controller - is this what you are hearing??

PS. there may also be a similar fan behind the dash -----there is on the W211 on some setups its between the ignition key and steering column behind a very small grill as part of the lower dash panel.

 

[K.Rob]

Thanks for all the advice. I'm going back.