The test supports that the problem is inside of the car, EXCEPT if the aux fan switch(blue two pole) is telling the A/C pushbutton that the engine is overheating.
Again the A/C pushbutton sends GROUND command signal to the pin # 10 on the KLIMA relay, that ground signal GOES thru the low pressure switch on the drier. SO if you run the car & have the air on there should be a ground signal at that switch as well. IF not then the A/C pushbutton isn't sending any signal. IF that is the case then you need volt/ohm meter tests on SENSORS to determine why not!
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)