gf6849p9900a

Inside rearview mirror dimming, basic function

Type gf · topic 68.49 · version 0103 · 2020-06-23

Applies to: Model all (CAR) with code 249 (Automatic dimming inside rearview mirror and outside mirrors)

Where it sits

Function group 3 Body › 68 Interior equipment › 68.49 Interior mirror - electrical system — Series 900 (models 9**) · Series 902 (models 9**) · Series 904 (models 918, 919, 924, 925, 938, 943, 957) · Series 906 (models 917, 918, 924, 953)

EinPAS 36 Visibility › 36.20 Mirror › 36.20.30 Inside rearview mirror — Series 900 (models 9**) · Series 902 (models 9**) · Series 904 (models 918, 919, 924, 925, 938, 943, 957) · Series 906 (models 917, 918, 924, 953)

Also applies to engines/gearboxes: 139 ***, 254 ***, 256 ***, 272 ***, 276 ***, 282 ***, 457 9**, 541 9**, 542 9**, 608 ***, 700 4**, 700 420, 700 421, 700 422, 700 423, 715 3**, 715 5**, 722 6**, 722 9**, 724 ***, 724 0**, 724 033, 724 044, 724 045, 724 1**, 724 103, 724 114, 724 115, 724 120, 725 ***, 725 0**, 725 035, 725 037, 725 038, 725 085, 725 1**, 739 390, 739 391, 739 395, 739 396, 739 397, 739 398, 739 399, 740 698, 743 3**, 743 4**, 743 498, 746 971, 924 9**, 924 910, 925 9**, 926 9**

GF68.49-P-9900A

Inside rearview mirror dimming, basic function

23.06.2020

Model

all (CAR)

with code 249 (Automatic dimming inside rearview mirror and outside mirrors)

General

The "Auto dimming inside rearview mirror" function protects the driver from being dazzled by following traffic.

Function requirements

No overvoltage or undervoltage

Circuit 15R ON

Reverse gear not engaged

Interior illumination not switched on

Function

For the function, two photo sensors installed in the mirror measure the brightness difference between the traffic area in front of and behind the vehicle. The inside rearview mirror evaluates the sensor signals and if the light intensity behind the vehicle is greater than in front of the vehicle, it dims the mirror glass.

For this purpose, the inside rearview mirror has a special electrochromatic layer on the glass. This contains electrolytes consisting of uniform crystals, similar to a LCD display. The inside rearview mirror applies a voltage to this layer, the crystals align themselves in a specific angle as a result. This leads to an immediate and depending on the light intensity and sensor measurement to a continuously variable darkening effect.

The inside rearview mirror also transmits the dimming request to the outside mirrors.

Additional basic functions

Automatic dimming of mirror glass of outside mirror, basic function

GF88.79-P-1000A

Function schematics

Function schematic for automatic dimming of mirror glass of inside and outside mirrors

Model 118, 167, 177, 247, 293 with code 249 (Automatic dimming inside rearview mirror and outside mirrors)Model 213, 238, 257, 290 as of model year 2021 with code 249 (Automatic dimming inside rearview mirror and outside mirrors)

PE88.79-P-2501-97A

Referenced documents