climate at the right time without function

good evening wikinger! yes as already described in the title the climate in the last weeks always worked worse. first came only more left cool air and now I notice no difference between climate on / off. have an appointment at the car driver club for climate service with filling etc. (that has helped two years ago) but somehow the system seems leaky. there are typical problems? evaporators I have read before. is that the same as “dryer”? and wi e do I find the leak? lg rainer PS: today I have 49.3 liters in fuelled I think I wouldn’t have come far