Auto-dimming interior mirror (BMW 3 Series E46)

The auto-dimming interior mirror smoothly dims at a certain light flow. It consists of a mirror element and an electronic device with two photo sensors.

Job

The electronic control unit "1" registers the light falling on the mirror from the front and from behind via photo sensors (2/3). If the light flow from behind is stronger than from the front, voltage is applied to the conductive coating "8". The coating is located between the glasses (4/6) of the mirror.

The applied voltage changes the color of the electrolytic layer "5". The higher the voltage, the more the mirror darkens. As a result, the reflection of the incident light flux decreases. 7 - silver-reflecting layer.

When reverse gear is engaged, the dimming effect is switched off. This allows you to exit a dark garage using the interior mirror.

Examination

1. Turn on the ignition.

You should not engage reverse gear.

2. Cover or tape the photo sensor on the front side of the mirror.

3. Shine a flashlight on the photo sensor on the back of the mirror. After a short time, the mirror should darken. The photo sensor is located at the top center behind the mirror.


(The original is located on the internet portal «BMWman.ru»)