Automatically dim driver-side exterior mirror, function - GF88.79-P-2003GH

MODEL 163 as of 1.9.99 with CODE (249b) Automatic dimming interior rearview and exterior rearview mirror (driver) 

Function requirements 

• no overvoltage/undervoltage
• Term.15R or 15 ON

Function 

The lens of the exterior mirror on the driver side is dimmed electrochromatically. The mirror glass between the reflector and the glass cover contains a layer of electrolyte gel. The light transmission ratio of this gel changes when a voltage is applied to it. The light hitting the surface of the mirror is more or less reflected due to the variable of the actuation voltage.

The dimming is controlled as a function of the ambient light, and the light striking the front of the mirror.

The actuation voltage is controlled by the interior mirror unit (A67)  (master) and the extended activity module (EAM) (N10/1)  . Separate cables are provided in this case for actuating the mirror dimming (M21/1h1) 

These two input parameters are detected by the ambient light sensor (A67h2)  in the interior mirror housing (rear) and by the mirror  dimming sensor (A67h1) in the lens of the interior mirror unit.

The interior mirror unit (A67)  is also the master for the exterior mirror dimming  (driver side).

If an interior light is switched on, or if the CAN message "reverse gear engaged" is received, the exterior mirror and interior mirror are brightened.