Wood,

With regard to the wiring diagram that I posted. In the index that lists all the compenents, the compenent number is listed down the left hand side and then the coordinates for finding it on the diagram are on the left hand side. Note that the Klima/Kickdown Relay is component N6 - on this diagram it is referred to as the "A/C compressor control module" and can be located on the diagram using the coordinates 7A. Also note on the diagram that component A9 is the AC compressor and the subcomponent x1 is the AC compressor connector (This is connector that you removed so that you could put 12 volts to the compressor clutch). Also, the wire colors are there to help you trace them.

More info on the Klima Relay
 

Once the Klima relay is out, take a look at the pins, notice that each one is labeled. The following posts have info about the function of each of the pins. The Klima relays being referred to in these posts are not exactly the same as the Klima/Kickdown relay in the 95 E300D, but as you will see they are pretty close. Between the wiring diagram and this info you will be better off in trying to locate your problem.

See post #5 here:
http://www.peachparts.com/shopforum/diesel-discussion/95748-anybody-have-part-003-545-6905-a.html

And post #21 here:
http://www.peachparts.com/shopforum/tech-help/102024-klima-ice-cube-not-working-2.html

After all the work, I found the problem is in the control unit (the one with push buttom to select AC on/off, Fan Speed), Now I got the AC on, but the AC cooling fan doesn't come on, and then it cause the comperssor shut off, Still working on it now, hope can get it running soon.

Nice work. What was the problem in the CCU? Just a bad connection somewhere? Let us know how everything turns out for you.

As a side note, I finally located and ordered the Klima/Kickdown relay for my car today, should be here by week's end. I am hoping that once I install it I will see al the strange problems I have had off and off disappear. The AC obviously wasn't working, but even when it was I was also experiencing: (1) evaporator freezing up, (2) defrost not really doing any defrosting (even though I changed out the cabin air filters), and (3) every so often a bouncing tach needle. I'm pretty sure with all the electrical connections that all of these problems could be related - recall that my Klima relay (because someone had installed it upside-down) was full of water and all rusted out! Anyway, I'll let you know how it goes. Good luck!

Thanks Tankowner, Two wire from the fan swith and one wire from the temperture control has bad connection, replace them with new wire from radioshark (only place I can find the wire that is small enough). But now I still has the AC fan to replace, look like it need to take off the bumper to replace it, any idea?

I just came across this picture again and it made me remember that I had planned to post a picture of it here - if only for posterity's sake. Thanks to the PO (or whoever) for taking out the KLIMA/KD relay and reinstalling it upside down so it slowly collected moisture! When I grabbed and turned it right-side-up and reddish-brown water start leaking out of it, I knew I found my problem.