2019 Audi A3 Sedan / S3 Sedan — Owner's Manual
The display brightness adjusts automatically to the brightness of the surroundings, both in the information and in the warning stage. In very dark or very bright surroundings, the automatic adjustment will set the display to the minimum or maximum level. In such cases, you may notice no change when adjusting the brightness, or the change may only be noticeable once the surroundings change. Adjust the brightness to a level where the display in the information stage will not disrupt your view ahead.
If you change the brightness, the display in the exterior mirror will briefly show the brightness level in the information stage. The brightness of the warning stage is linked to the brightness in the information stage and is adjusted along with the information stage.