The IHKA system is set into operation by pressing the + button on the driver's side from zero position (precondition, terminal 15 ON). The required air flow rate can be set separately for the driver and passenger with only one blower motor. The blower stages are shown in the display in the form of two 14-stage blower indicator wedges. If the blower control is in automatic mode, the indicator wedges are blanked out and the lettering AUTO appears in the display.
Separate air flow control is achieved by means of a programmed characteristic map which influences the ventilation flaps as well as the blower output corresponding to the settings of both blower rocker switches.
An increase in the set air flow rate due to the driving wind is essentially compensated by the fresh air flap closing dependent on the vehicle speed.
This air flow rate influencing option has rendered adjustment at the ventilation grills unnecessary.