9-3 XWD (9440) L4-2.0L Turbo (B207R) (2009)
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The ACC unit grounds each winding (pin 10, 27, 11 and 12 in K32) in a specific order thus operating the motor in short pulses, which explains the name
stepping motor. The rotational direction can be changed.
When the stepping motor is stationary, two windings are continuously grounded in order to lock the motor. The stepping motor does not need to be
reconnected to the control module (position sensor). By sending a specific number of ground pulses, the ACC unit knows how far the air distribution
damper has moved.
Wiring diagram
