Defroster for windshield not working

2001 BMW 318I
200,000 MILES • 2.0L • 4 CYL • 2WD • MANUAL
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BMWE46318I
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The defroster for my windshield does not work, so when I drive in windy/cold/rainy weather, it gets all foggy, which makes me have to drive with my window down or else I won't be able to see through the windshield. Every other vents in the car works, both with cold and warm air. So it's only the vent for the windshield that is malfunctioning.I do not know if this has to anything to do with the problem, but when I turn on the my car, there seems to be a knocking sound for maybe 1 minute or so from the vents in the front/radio unit. Do you have any idea what that could be about?
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Jan 25, 2021 at 9:17 PM
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BMWE46318I
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I have been told that it possibly could be the blend door actuator, but where is that located on my BMW E46 318i from 2001? Please I need help.
Jan 28, 2021 at 11:40 AM
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ASEMASTER6371
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Good afternoon,

There is a defroster flap door motor that controls the opening of the vent. It sounds like that motor is bad.

I attached the location of the motor for you on the heater case.It is under the dash and not much involved in changing the motor. Remove the connector and the screws that secure it to the case.

Roy

Air Distribution

Air distribution
Air distribution for defrosting, ventilation and footwell is controlled by buttons on the operating panel and the 3 bipolar stepper motors via the M bus (motor bus). Manual or automatic air distribution can be selected. The motors are coded and can only be installed in the designated position. It is not possible to interchange the motors.

The LED in the AUTO button lights during the automatic program. The opening angles are set automatically depending on the interior temperature, outside temperature and set point temperature.

The air distribution can be set individually in manual mode. The setting is indicated by an LED in the selected button on the operating panel.
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Jan 28, 2021 at 1:54 PM
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BMWE46318I
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I changed the motor and now it is fresh. Thank you for you help!
Jan 30, 2021 at 10:05 AM
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ASEMASTER6371
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You are welcome.

Always glad to help.

Roy
Jan 30, 2021 at 2:34 PM