I read and re-read this thread xx times. I also went back to the archives and the climate control manual.
First M.B.DOC said in one thread:
"To determine whether the problem is inside OR under hood, you must see if the pin number 10 on the "klima" relay gets a GROUND command signal from the pushbutton assembly. WITH the car running measure for battery voltage between pins # 5(power) & pin # 10, IF you have battery voltage then the problem is in the "klima" relay." This is step #2 in job 83-605. I got battery voltage.
Second, as I mentioned before, the system passed all the steps in job 83-605 in the climate control manual. However, the next box after passing the last step (#6) says "renew control unit (N6)"or Klima relay.
Third, you said earlier:
"The next readings say that the PBC is pulling the Klima to ground."
Conclusion: I have a bad KLIMA relay.
Thanks for you help and remember you ONLY have 27 years of experience on me!
I will report end result sooner or later to hopefully help somebody else...