Air flow treatment assembly for a vehicle comprising a transmission system for remote control of the means for controlling the flow of air

An air-flow-treatment assembly for a vehicle, comprises: a supporting structure (11) carrying at least one heat exchanger (12) for treatment of a flow of air; control means (13, 14), for controlling the temperature and/or the distribution and/or mixing and/or air intake of the flow of air; and at least one transmission system (15) comprising a retention device (19) for withholding said control means (13, 14) in a plurality of stable positions. The retention device (19) comprises: a rotatable transmission member (20); at least one pair of walls (27) forming an arched groove (28) that is concentric with respect to the axis of rotation (21) of the rotatable transmission member(20); and at least one engagement member (31), fixed to the rotatable transmission member (20) and mobile within said arched groove (28).