Hi all,

New to the forums, but not new to my 1992 320CE

in fact, I've owned it since brand new



Story-

My C124 has suddenly developed a loud buzz from behind the glovebox,
after taking apart the glove box liner, i've located it to this part 1248001378.

Hoping someone here could tell me what this part does and which vacuum hose goes into each outlet- Google says its a Climate Control Air Diverter Valve, but I have no idea what its function is, since my AC still blows cold and I'm still able to divert AC to different outlets via the twist knob.

more to the story:
Since its a public holiday here in Hong Kong today, I've decided to drop by a scrapyard where they have a couple of w124s lying around to get me another one of this part to test it, replacing it without knowing if it works properly (i was just trying my luck). But unfortunately, the same loud buzzing noise persisted on the scrapyard part.



Would anyone here be able to shed some light to this problem because I haven't seen any posts online about this part failing?

The loud buzzing sounds exactly like a vacuum pump with a torn diaphragm.


I just wanted to make sure before I start throwing $177+shipping into replacing a part that isn't the problem.