Not enough coffee in the system. Too long of a Monday...

Right, the coolant microswitch - Not sure of the cutoff, but later cars (I know the 350SDL and 2.5 Turbo W124) used the thermistor in the head and had the ACC do the high temp cutout control. The number of variations in the Klima relay is truly ridiculous over the years. It's almost like they changed it every year! I guess the good news is that they all seem to use the same pinout, so if in doubt, the '86 version that used all of the pins should work for any of them.

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Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]