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Stepper Motor Locations

Air distribution of the IHKA E38 (for example) is regulated using stepper motors. There are 10 stepper motors used for air distribution including:

Fig 1: Identifying Stepper Motor Locations
G03389492Courtesy of BMW OF NORTH AMERICA, INC.

Of these 10 stepper motors, the Fresh Air Flap stepper motor is operated as on previous systems. It has four circuits that control the motor rotation with a 500 Hz signal at each circuit as needed.

The remaining 9 stepper motors each contain a microprocessor that monitors operating signals on the M-Bus. When a specific signal is "heard" on the M-Bus the motor is activated by the microprocessor to carry out its function. Therefore, correct location by part number is critical.