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Garage => Mechanicals => Topic started by: avantbenz on 10 June 2019, 04:10 PM

Title: What parts are these (related to the climate control vacuum system)?
Post by: avantbenz on 10 June 2019, 04:10 PM
I'm trying to get my air conditioner working in time for summer and obviously getting a late start. This involves tearing apart my dash and looking for things that are old and probably need replacing.

I found a yellow vacuum modulator type thing that doesn't seem to hold vacuum (although I'm not sure it's supposed to so there is that). Can someone please identify this and point me to a place I can buy it?

And this other black mod type thing also isn't holding vacuum. Does it need replacement? Any tips on best places to buy it? I found a few but always open to suggestions.

Pics here: https://imgur.com/a/sw7eaf7

Title: Re: What parts are these (related to the climate control vacuum system)?
Post by: avantbenz on 11 June 2019, 12:33 AM
The black vacuum modulator thing is labeled: 123 800 0578 but I'm actually having a hard time finding it for sale. Lots of similar looking parts are popping up but none with the exact same part number. Please help!
Title: Re: What parts are these (related to the climate control vacuum system)?
Post by: Alec300SD on 11 June 2019, 07:20 AM
It is a check valve and should hold vacuum when suction is applied to  the side opposite the black end (blue or white).
If it failed, just substitute the cross referenced MB part number 123-000-00-78 .
Title: Re: What parts are these (related to the climate control vacuum system)?
Post by: avantbenz on 11 June 2019, 12:29 PM
Thanks Alec300SD, I ordered the 123-000-00-78 via Amazon and it should arrive tomorrow.

I'm holding out hope someone knows which part the yellow valve is and where to find it. 
Title: Re: What parts are these (related to the climate control vacuum system)?
Post by: Alec300SD on 11 June 2019, 09:41 PM
Two yellow vacuum switches (item 20 and 23 on page 9 of the pdf) MB part number 000-800-05-73.
http://handbook.w116.org/Climate/83-600.pdf

Available at the dealer, or online.
https://www.mboemparts.com/oem-parts/mercedes-benz-switch-ventilation-0008000573

Not sure how to test them though.
Title: Re: What parts are these (related to the climate control vacuum system)?
Post by: avantbenz on 11 June 2019, 10:38 PM
Wow...that PDF is terrifying and potentially invaluable. So many things that can go wrong it makes me cross-eyed. Thank you for the resource and the info, Alec300SD.

Can anyone chime in on thoughts of how to test the vacuum switch? It's about $25 and I'd rather not buy it unless I knew for sure it didn't work.