On the driver's and passenger's side, a separate choice can be made between 3 different automatic blower settings (LOW, MED and HIGH) and a MAX setting.
Without dynamic pressure compensation, as the driving speed increases, the air volume at the air inlet duct also increases disproportionately. This effect can be compensated for when the fresh-air flap, controlled by the speed signal (K-CAN message), reduces the size of the air inlet channel. In order to avoid continuous adjustments of the flap due to only slight changes in driving speed, the calculation of the target position from the speedometer output signal is delayed.
The backpressure characteristic curve is extended into a characteristic map by including the blower output.
With the convertible top opened, the backpressure compensation is disabled.
The blower output is raised or lowered under certain circumstances:
In order to be able to cool down or heat up the interior in the case of extreme interior temperatures, the blower output is raised automatically depending on the setting for the driver area.
The maximum blower value is limited depending on the coolant temperature.
If the vehicle voltage drops below a certain limit value, the power module initiates a reduction in the blower output via the body CAN SYSTEM.
In order to relieve the load on the car battery during the starting sequence, the blower is switched off. However, a fault in the bus transfer of the message ”Terminal 50” could mean that the blower is shut down. This is why the duration of the active state is evaluated. The status ”terminal 50 physically on” is inverted if:
The previous status is then regarded as invalid. No fault code entry is made in the fault code memory, but the function is then ”logically off”. The blower deactivation remains inactive until terminal 15 is de-energised. In the case of terminal 15 new start, the fan deactivation becomes active again.