Air flow swiching system for a vehicular air conditioning system

The air distribution unit (1), for a motor vehicle air conditioning system, has a distributor (9) with a truncated cone shape, with rotary settings around its longitudinal axis (10). It has an axial inflow opening (11) which is linked to an inflow zone (3) in each rotary setting of the distributor. The distributor has an initial radial outflow opening (17) around a leading axial section (16) of the distributor which is linked to the axial inflow and connected to an outflow zone (13) which, according to the distributor rotary setting, gives a flow which is increased or decreased or stopped. The outflow zone is connected to a second offset outflow zone (14). The distributor has a second radial outflow opening (19), at a second axial section (18), linked to a third outflow zone (15), with a flow set by the rotary setting of the distributor at an increased or decreased rate, or stopped.