The fan N85 receives an ignition operated power supply (INT/A) from a line protected by fuse F31 of the junction unit under the dashboard B2 and controlled by relay T8 and dedicated fuse F8 of the engine compartment junction unit B1 .Control knob H81 controls the fan at different speeds via regulator O30: the command signal varies according to the position of the control knob and the resistances of regulator O30 to determine four different voltage signals for the fan N85 which turns at 4 different speeds.Outside air intake/recirculation flap motor N82 is controlled by a button located in control unit H80: The engagement of the button sends an earth signal and a power supply signal - ignition operated line (INT) protected by fuse F51 of the junction unit under the dashboard B2 - which are inverted in order to invert the rotation of the motor.