I purchased a 2007 C230 Sport in December of last year and since then I have had 2 issues with this very, very annoying chirping noise coming from the dash board somewhere. I took it in once for it, it didn't do it for about 3 weeks and now it's back and more annoying than the first time. The dealership out here sucks and I'd like to see if anyone else has had this problem and knows what needs to be done to make it stop. I'm forced to listen to the radio and mind boggling levels to drown it out. Help?!?!

 

there is a plastic clip that rubs up against the fire wall in the engine compartment. this noise travels through the fire wall and into the dash area, thats why you hear it in the dash. just open your hood and look for a black plastic clip in the center rear of the eingine compartment. this clip hold some engine wiring harness. just cut that plastic piece that rubs on the firewall and it should go away. i have had at least 3 cars with this issue, could be what you have.
hope this helps

 

Exactly. I had the same issue on my 2007 C350. It was driving me nuts and I took it to a dealer in Chicago and they were clueless. I spoke to another dealer and found out thatthis issuewas communicated through a shop foreman conference so most dealers should know about it. I found the piece of plastic that was rubbing on the clipthat supports the harness from the firewall. I cut it off (the plastic flash sticking up)and the noise finally went away!

 

I had the same problem with my 2007 C 230 Sport thatI bought in December of 2006 as well. I took it the dealer and they were aware of the problem. I guess it is common. They fixed it pretty quick (they had to glue something under the dash) and washed my car inside and out for free (good service ).

 

Could somebody take a photo of this plastic clip and where it is in the engine compartment. I just spent ten minutes looking for the dern thing and have no idea where it might be. I don't see anything like that in the rear of the engine on the firewall. Thanks.