2009 ML550 RATTLE IN DASH

I have a rattling noise inside the dash that only expresses itself intermittently on rough roads. It sounds like something is rattling inside, but doesn't happen until I hit a patch of rough road at speed. If you put a pencil inside the a/c vent and move it quickly left and right, that's what it sounds like, but deep inside. It is loudest near the speaker in the center of the dash. Covering the a/c vents with my hands only muffles it.
When I park for the night, the noise might not come back for days. It is completely random. But when I hit something that dislodges whatever is rattling, it keeps rattling for the rest of the trip -- loudly on rough roads, more diminished on good pavement, nothing when stopped at a light or intersection.
This is driving me nutz. Any ideas on where to look, what to check? I was thinking an inspection camera in the a/c vents while driving but I think the vent tubes don't head down into the dash, I think they go sideways, but I am not sure.
HELP!




Last edited by flybd5; Oct 16, 2014 at 08:01 AM.

The dealer also mentioned temp sensors behind the a/c vents that may be loose but that's for them to look at afterwards.

The dealer also mentioned temp sensors behind the a/c vents that may be loose but that's for them to look at afterwards.
However, at the same time they found that the rough idle they had previously written off as something related to the brake springs was actually a defective engine head that was causing compression loss in at least one of the cylinders.



Trending Topics
The Best of Mercedes & AMG


