Heater or air conditioner for vehicles

Heating or air-conditioning system for vehicles comprising:

• a cold-air duct and a warm-air duct which open out into an air-mixing chamber,
• a first control member, assigned to the cold-air duct, which sets the amount of cold air which flows into the air-mixing chamber, and
• a second control member, assigned to the warm-air duct, which sets the amount of warm air which flows into the air-mixing chamber, the second control member being designed as a shutter having a plurality of pivotable closure lamellae which are arranged next to one another, overlap one another in the closed position, and can be pivoted by a common actuating drive,
• wherein the individual closure lamellae, when pivoted out of the closed position, open up unevenly sized opening cross sections for the warm air to pass through, the sum of the unevenly sized opening cross sections being such that a predetermined amount of warm air is fed to the air-mixing chamber as a function of the actuating travel of the actuating drive.