Clicking under dash
 

Ok, yet another "new" thing. My ac and flaps appear to work ok, but once in a while I hear a clicking from passenger side near trans tunnel up by lower dash. If I switch CCU off, it goes away. Is this an indication that the vacuum control manifold/elect. is starting to go? Is it possibly repairable?
Thanks!
'87 300SDL

Yes, it's gone. Don't believe that model is repairable.

Thanks..something to do this weekend :)

fellow engineer jeremy5848 cracked one open and found bad solder joints...

http://www.peachparts.com/shopforum/diesel-discussion/281695-w124-climate-control-vacuum-valve-repair-diy.html