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Discussion Starter · #1 ·
Can the passenger side mirror have auto dim? My two other mirrors dim just fine but never see the passenger side mirror dim. Can't find anywhere in the manual telling if whether that mirror is supposed to dim.
 

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Can the passenger side mirror have auto dim? My two other mirrors dim just fine but never see the passenger side mirror dim. Can't find anywhere in the manual telling if whether that mirror is supposed to dim.
If you're seeing the driver side mirror dim but not the passenger side, it may be because the most frequent reason you get the driver side to dim is from the low beam of vehicles behind you, travelling on the same direction but on lanes to the left of you. The low beam pattern allows for more illumination above the horizon for the same direction of travel, but not opposite. This is to prevent blinding oncoming traffic. The same beam may get blocked by a good amount by your vehicle before it makes the right side mirror dim.

I suppose you can shine a flashlight directly on the right side mirror to test.
 

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Discussion Starter · #4 ·
If you're seeing the driver side mirror dim but not the passenger side, it may be because the most frequent reason you get the driver side to dim is from the low beam of vehicles behind you, travelling on the same direction but on lanes to the left of you. The low beam pattern allows for more illumination above the horizon for the same direction of travel, but not opposite. This is to prevent blinding oncoming traffic. The same beam may get blocked by a good amount by your vehicle before it makes the right side mirror dim.

I suppose you can shine a flashlight directly on the right side mirror to test.
I can see that sometimes the sensor is not triggered because of light beams. But it is hard to believe that through over a year of ownership neither my wife or I has ever seen that mirror dim, even when driving on multi-lane highways.

I will try the flashlight. I suppose the sensor is somewhere close to the mirror?
 

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I can see that sometimes the sensor is not triggered because of light beams. But it is hard to believe that through over a year of ownership neither my wife or I has ever seen that mirror dim, even when driving on multi-lane highways.
The low beam pattern is specific enough that the chance of the passenger side mirror getting enough light to dim might be small. Here's a snapshot I took of how the low beams in a Left Hand Traffic / Right Hand Drive region (i.e. opposite of how it is in the US), where the ECE beam pattern shines a lot more light above the horizon on the left side. In the US, this would be the opposite. You can imagine if all the low beams behind you, from vehicles travelling on the same direction behave like that, then the driver side may see more light for the dimming function to respond to.


Here's a low beam pattern for the US (i.e. US DOT) from a farther distance. One of the differences is that the upper flare doesn't go as high, but side view mirrors can be just within reach of that upper right region.


I will try the flashlight. I suppose the sensor is somewhere close to the mirror?
I'm not sure. If you have 360 view, there is a camera lens under the side mirror, pointing down/back. That is not it.
 

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I will try the flashlight. I suppose the sensor is somewhere close to the mirror?
Odd. According to this Volvo accessory page: https://accessories.volvocars.com/en-md/XC90(16-)/Accessories/Document/VCC-515593/2018

Autodimming is connected to the dimming in the interior rear view mirror and they have a common sensor located on the interior rear view mirror.
The user guide describes where the interior rear view mirror's dimming light sensor is. So, that's the only place then, and not individually on the sides.
 

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Discussion Starter · #7 ·
The user guide describes where the interior rear view mirror's dimming light sensor is. So, that's the only place then, and not individually on the sides.
So that means the mirrors should dim at the same time.

Sent from my SM-N950U1 using Tapatalk
 
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