Hello Everyone,
Long time reader that recently signed up as I have a problem with my 86 560SL AC and could find nothing via the search to help.
Everything seems to test OK, but the compressor will ONLY kick in if I bring 12 volts to it directly at which point the AC blows ice cold.
Right now it seems to be getting a dribble of power as the clutch ever so slightly engages, where by I get about 1 jerky/hesitant revolution every few seconds.
I'll list what i know thus far:
Charge is good (still R12)
AC Relay swapped with known good
Klima push button SWKG
Temp control relay SWKG
Cabin temp sensor SWKG
Evap temp sensor SWKG
Fuses/contacts have all been changed with copper and cleaned.

One thing that is strange is the aux fan is on all the time unless I pull the leads feeding it.

I'm waiting on my service manual from MBUSA with the hopes of printing off a wiring diagram but Any thoughts/avenues I might pursue in the mean time would be appreciated.

Many thanks to everyone!

Glen in NY