I replaced the evaporator core in my 1997 w140 s320 and i've been putting the dash back in i've found a plug and i can't find out what it goes to.

It's on the passenger side dash area, comes out from behind the windshield brace.
It's taped up with the airbag and glove box light.
Has 3 prongs, part number 014 545 00 28.
3 Cables, Yellow w/ blue stipes, brown, and grey w/ red stripes.

Anyone have any ideas?

I am totally in ignorance as regards the answer to your question, but I see you have had no replie's. So, I just respond as to possibilitie's based on thing's I've seen with Detroit Iron vehicles. On old (maybe new, I don't know) Detroit cars it was not uncommon to find plugs that have no place to hook up, but are just legacy things that only had function if your purchased certain option packages. It was much cheaper to use the same wiring harnesses, than to have harnesses different dependent on which options you bought. Secondly, though I'm sure you've already looked extensively, from the last point the plug wiring was affixed under the dash, means that it's mate must be within the possible radius. I hope you get a knowledgeable response quickly. I wonder if there are website's with electrical schematics for the W140 that are free.

How about this.

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S320L -97

Incredible link.

Mite that be some kinda computer scan connection?

i found it gentlemen, twas the switchover valve located inside the vaccuum box. Thank you.