My car is in the shop and they gave me an '07 C230 sedan to drive with 6K miles on it. As SOON as I left the dealership,
that car had a brutal squeaking noise kinda like a repetitive chirping coming from what seemed like the center of the dash.
VERY irritating to say the least. I would have taken it back immediately for another car it was so bad, but I was already out
on the freeway, and I thought of something I had read here on this forum about this problem MB has had with these cars and
this particular squeak. I remembered that it was something NOT inside the car, but under the hood in the rear by the firewall.
So, I took the car home, popped the hood, and looked in back of the engine up against the firewall.....and found what I had
remembered was the problem. Look for a braided nylon sheath with wires in it maybe 1/2 inch wide. It's held to the firewall
by what looks like some kind of fancy plastic clip thingy. Love that word "thingy". I pulled the sheath OUT of the clip and sort
of pulled outward on the plastic clip (away from the firewall). Looking at it, I thought........there's NO WAY that piece of plastic
and a nylon wiring harness could be making a loud chirping noise inside the car. No way. I would have bet on it. And, once again,
I would have lost that bet. Took the car for a test ride and GONE. Somebody posted about this, so I apologize and not trying
to rip off anybody's post, but.....I wouldn't have believed it myself if I hadn't heard it. It really sounds like it's right there
inside the car.

Maybe by posting this (again) now, it will save somebody a lot of grief tracking this thing down.
The cure might be to take a nylon wire tie or something and re-do it and then test drive it.
I'm not sure how many model years this problem is applicable to, but.......

mrcoyote[8D]

 

mrcoyote, thanks for the advice on your post. i have a 2007 C230 with 6,500 mi. on it and it has been doing the same crap for about 500mi. i was going to take it to the dealer and have them fix it but i'll try your suggestion first. thanks again.

hwfrog

 

Apparently, the dealerships know about this due to a "memo" or "service bulletin" they received, but I was surprised that MY dealership
(OF COURSE) did not know about this. [:@] I had to show them. Funny, huh. And it wasn't even my car! Even funnier. Anyway, I hope this
does it for you and some mechanic doesn't take half the car apart looking for it. Or worse, the whole dash out. I had this done on my previous
vehicle, a BMW, and after they took that dash apart, the car was never the same. Hope it works for you....remember...you may have to pull on
it and reposition that plastic "clip" that holds the wiring a couple of times to get it to go away completely. Again, don't even ask how a plastic
clip could be making such a noise, but it sure does make an irritating squeak, doesn't it?

 

So there should be some wires i have to move away from the fire wall, and that it?

 

R>
see previous posts of mine for the easy fix.

 

Thanks for the (re)post! I began to experience this problem with my C and was losing hope of finding the issue. NEVER would have thought the nylon braided hose would have been the culprit. Car is extremely quiet again.

 

Hi to all. Anyone got any photos of offending item? As the sqeaking is driving me mad but, iv'e looked every where for this braided hose and clip on the firewall (driver's side?) and can't see anything like what has been described, sorry. W203, 2002, 270 CDi.

Regards

Keith

 

Thank You, Thank You, Thank You! The squeaking was driving me nuts!!! I could swear it was coming from inside the car!

 

So, you mean I have to cut the plastic "thingy" to loosen up the cables? I don't know... The noise doesn't seem to come from there. It sounds like it is inside the dashboard, by the glove-box, or comewhere there. The sound is not heard outside the car, only inside.
Thanks a bunch.

 

The white plastic clip correct? That chirping is driving me nutty!