The kickdown solenoid on my '87 190DT is powered through the Klima. Powered is the operative word...the Klima only controls it in the sense that if the Klima fails, you have no transmission kickdown. I think the idea is that if the Klima shuts down due to belt failure, it's a good idea not to run the engine at high revs. On most of the gas cars, kickdown power is supplied through the fuel pump relay.

Pin 12 is the coolant thermoswitch. With some versions, the ACC (rather than the Klima) will control fan and compressor using a thermistor rather than a thermoswitch.