W126 1983 SD climate control problems?

[R L Lepper]

I have a problem with no Power to the AC clutch. I can power at the lo pressure switch and ingauge system and the comperssor will ingauge and run. The sight glass clears up so I know it has freon. This happened all at once . Have no fuses blown. Does this power come from the ETR Switch? Or Switchover valve?I would also like to know the Fresh air flap green and rd vacuum hose connections to the vacuum 2 stage morors. for the main air flap.

[LUVMBDiesels]

Do a search on KLIMA. The older SDs have a smaller version of the KLIMA relay inside the fuse box. If you can jump the sockets ( I think it is 5 and 7 but look it up first) and the compressor goes on, then you either have a bad relay OR a burned out CCU. I had a burned out CCU in my 1981. WHat I did was remove it from the car (the hardest part is taking all the switches out of the panel and disconnecting them) take the CCU into the house and opened it up. You will have to remove the temperture wheel and the fan controls before cracking open the main unit. Inside there are two circuit boards and connectors running down each side. Check the connections with a continutity tester. I found that some of the solder joints from the boards to the connectors had cracked AND that I had a burned out trace on one of the boards. I simply touched the soldering iron to each solder joint and remelted them to fix the cracked joints. I ran a small piece of fine gauge wire from one end of the burned trace to the other and then buttoned everything back up. To my amazement it worked!

[R L Lepper]

Thank you for your reply. I had already switched the relay for another relay so it will likely be the CCU. My wife told me a week or so ago that she had seen smoke under the hood when she started home from work but I had not found anything not working at that time.