Abstract: A control device for an air conditioning installation of the passenger space in a motor vehicle comprising a single actuating member, such as a finger, displaceable between two end positions along a linear path and acting on transmission means for controlling means for distributing air through several air blowing vents, for controlling the switching on or off of the electrical motor of one ventilation fan and for adjusting a heater in such a way that for each position of said member correspond states of the distribution means, of the ventilating fan and of the heater which allow reaching comfort conditions in the vehicle passenger space. The transmission means are formed so as to act on a rotating switch allowing establishing and interrupting circuits for operating air distribution flaps and switching on or off the electrical motor of the ventilating fan, and on a hot water admission cock for setting the heating power.