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Perhaps about 10% of the time that I drive my car in the daylight, the driver's side mirror is super dark. I assume this is something that is supposed to happen at night when a car is pulling alongside you so that the headlight glare doesn't bother you, but this is happening in the daytime and it isn't just the perfect angle of the sun shining brightly on it. It makes it difficult to see anything in that side mirror when it happens, and it stays that way the whole drive.
Is this some sensor going bad? Has anyone else experienced this?
I've had it happen very occasionally, I believe the sensor is in the interior rear view mirror so maybe the sun is hitting that at a strange angle? When it happens next put your hand over the rear view mirror and if the side mirror clears then that is the problem.
Depending on the year of your R231, There is also a control unit (231-900-90-06) in the door which can act flakey. See the WIS attached electrical function schematic.
Sometimes it’s just a question of reseating the connectors, but I’ve also had cars that have had seat memory/movement issues, as well as mirror issues traced to this control unit. I believe the sensor in the rear view mirror also plays a part in the dimming of the side view mirror. See #2 in .pdf (Mirror dimming, request)
This usually stores a trouble code that can be read in XENTRY.
Good Luck
Last edited by crconsulting; Jul 14, 2023 at 12:45 PM.
At the correct time of day with Maryland summer sunshine I have seen my mirror darken from time to time during the day. I have never given it a second thought as it never stayed that way for long, or I wasn't driving long enough to notice it anymore. I did notice it when it initially happened though. Day darkening has never caused any issues with me seeing during the day and the mirror does not remain that way for extended lengths of time. The mirror switches back to normal at some point. I can't remember the last time it has darkened during the day, but it doesn't happed often. If it happened every day, or remained darkened for extended times I would likely have it checked out by MB
Originally Posted by billvp218
Perhaps about 10% of the time that I drive my car in the daylight, the driver's side mirror is super dark. I assume this is something that is supposed to happen at night when a car is pulling alongside you so that the headlight glare doesn't bother you, but this is happening in the daytime and it isn't just the perfect angle of the sun shining brightly on it. It makes it difficult to see anything in that side mirror when it happens, and it stays that way the whole drive.
Is this some sensor going bad? Has anyone else experienced this?
Last edited by ThatsMyDawg; Jul 18, 2023 at 08:39 PM.
At the correct time of day with Maryland summer sunshine I have seen my mirror darken from time to time during the day. I never given it a second thought as it never stayed that way for long, or I wasn't driving long enough to notice it anymore. I did notice it when it initially happened though. Day darkening has never caused any issues with me seeing during the day and the mirror does not remain that way for extended lengths of time. The mirror switches back to normal at some point. I can't remember the last time it has darkened during the day, but it doesn't happed often. If it happened every day, or remained darkened for extended times I would likely have it checked out.
Yeah, when it happens with mine, it stays dark until I turn the car off. It's pretty dark when it happens, and I can't really see much of anything out that side mirror.
Yeah, when it happens with mine, it stays dark until I turn the car off. It's pretty dark when it happens, and I can't really see much of anything out that side mirror.
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