An operating panel for an air-conditioning system equipped with a heating device and a cooling unit comprises a plurality of actuating elements for setting the rotational speed of a blower, the incoming-air temperature, the air distribution, and the fresh-air/circulating-air damper. A switch arranged in the operating panel serves to switch the cooling unit on and off. A maximum cooling switch sets the air temperature to maximum cooling in the vehicle passenger compartment by coupling the maximum cooling switch to the fresh-air/circulating-air damper, on a blower step switch, which controls the blower motor, and the cooling unit switch. Thus, a single switch conveniently and automatically sets to the maximum cooling setting.