Automatic dimming outside mirror and inside rearview mirror, function - GF88.79-P-2010RF

Model 205, 253 with code 249 (Automatically dimming mirrors) 

Function requirements, general 

• No overvoltage or undervoltage
• Circuit 15R ON
• Reverse gear not engaged
• Interior illumination not switched on

15RThe circuit status is sent by the electronic ignition lock control unit (N73) over the interior CAN (CAN B) to the front SAM control unit (N10/6).

Automatic dimming outside mirror and inside rearview mirror, general 

The mirror glass on the inside rearview mirror (A67) and left outside mirror (M21/1) dims electrochromatically. This is realized by a layer of electrolyte gel in the mirror glass which controls the light permeability in increments depending on the voltage applied.

Automatically dimming outside mirror and inside rearview mirror, function sequence 

The inside rearview mirror senses the ambient light via the mirror dimming light sensor, forward (A67h1) and the light hitting the mirror glass via the mirror dimming light sensor, rearward (A67h2).

The inside rearview mirror evaluates these input factors and sends the mirror dimming request via roof LIN (LIN B13) to the front SAM control unit. The front SAM control unit sends the dimming information over the interior CAN to the left front door control unit (N69/1).

The left door control unit receives the dimming information and supplies the corresponding actuation voltage to the mirror dimming (M21/1h1) of the left outside mirror. The mirror glass of the inside rearview mirror is dimmed by the inside rearview mirror itself by means of activation of the inside rearview mirror dimming (A67h3).

If an interior illumination is switched on during mirror dimming or the reverse gear is engaged, the dimming is interrupted.