Automatic dimming interior rearview mirror, function - GF68.49-P-0003S

MODEL 215, 220 

Function prerequisites 

• No voltage or voltage too low
• C. 15R or C.15 ON

Function 

The interior rearview mirror unit (A67)  can be dimmed electrochromatically. For this purpose, a layer of electrolyte gel is located in the mirror glass between the reflector and the cover lens. Voltage connected to the gel modifies its permeability to light.

The light reaching the surface of the mirror is reflected to a greater or lesser extent due to the magnitude of the actuating voltage. The actuating voltage is controlled by the electronic circuitry in the interior rearview mirror. This procedure is subject to the ambient light and the light reaching the mirror.

These two input variables are sensed by the ambient light sensor (A67h2)  in the mirror housing (rear side) and the automatic dimming interior rearview mirror sensor (A67h1)  in the mirror glass of the interior rearview mirror unit (A67) 

If an interior light is switched on or the reverse gear (CAN message) is engaged, the interior rearview mirror is always  switched to a brighter setting. This is accomplished by an additional signal lead from the overhead control panel control module (N70)  to the interior rearview mirror unit (A67)  .

The interior rearview mirror unit (A67)  serves also as master for the automatic dimming exterior rearview mirror  (driver's side).