Climate cools only with “LO” display

Hello guys, can that be asked that already, but I found nothing about the search. My climate cools only if I turn down the temperature to the display “LO”. If I turn even a degree higher, so to 16, comes immediately warm air again. Since it cools with LO it probably can not lie on the coolant. Possibly the temperature sensor? My feeler for the outside temperature is also there. Can this also be related to it? Would be nice if someone can help me. Thank you and greeting Heiko