The invention relates to a control device (1) for controlling airflows in motor vehicles, comprised of a frame having at least one passage opening (4) and at least one controlling means, which is provided in the form of a roller louver (5) and which serves to modify the passage cross-section for the air flowing through the passage opening (4). The frame comprises a housing (2) with at least two hollow bodies (8) that are open along the longitudinal sides. These hollow bodies (8) accommodate the drive shaft (6) or the return shaft (7) for the roller louver (5), and each have a pivotal cover (8.3) for opening the respective hollow body (8). The control device (1) can be mounted inside airflow ducts of a heating and/or air-conditioning system for motor vehicles.