How well does your auto dimming rearview mirror work?

[Cooper993]

Compared to my B5 S4 and other vehicles I have, the auto dimming rearview mirror in the B8 S4 sucks.

It takes a long time to dim, and it doesn't dim that much. It won't dim at all during dusk/twilight and only when it's total dark

Is it just me or are they all like that?

[LYKUNO]

My 2011 behaves similarly - never seems to be dim enough. I wish it had the old technology where you flip a lever that moves the mirror to dim, but that's progress for ya!

[b8audis4]

Yes it doesn't dim that much! My 335i dimmed too much though and it really bugged me how much the side view mirrors dimmed because sometimes you wouldn't see a car if their headlights weren't on. I would rather have less auto dimming.

[jlaudio]

Wouldn't know, my car doesn't have it. I have 3M Crystalline on the windows and that gives me little to no glare whatsoever. Both my b7 s4 and a4 both were too dark with tint on when the mirror dimmed.

[levigarrett]

I really like mine? I think they dim quite well. I wonder if there was a change on the 8.5? I dunno but I took a 4 hour highway drive last night and noticed the mirrors working the entire time. Was nice.

[SwankPeRFection]

I've not had issues in mine. Seems to behave similar to the ones in the B7... maybe a bit less, but certainly not less as to cause blinding issues.

[AKPS4]

never noticed mine work even once, but i think that may be because of my 18% tint all around... lol. I've never had an issue with bright lights from behind because of the tints so cant really complain about it.

I have to say, the auto dim in my nissan maxima was fantistic though

[Schadenfreude]

You are not alone. I find myself having to adjust my rearview mirror all the time. Sometimes it seems like it hasn't adjusted at all and other times it seems to change midday with no change in daylight.

[milk242]

Coming from a 2004 civic, the rear view mirror seems fine.

[Pilfer]

No problems but I have 35% tint


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[A4 Joe]

Never noticed the mirror ever dimming. I have not been bothered by glare.

[TDIaholic]

Mine works OK but sometimes the dimming seems too slow. It definitely does dim though.

FYI, you can also remove th auto-dimming mirror and replace it with a manual filp-up mirror. I used to have a mirror like this in my car but took it out when I fitted my auto-dimming one. It's similar in shape to the auto-dimming mirror so it fits over the rain sensor, etc. just fine.

[Carbines]

My B8 behaves similarly to yours. Other cars I own/owned had more effective auto-dimmer mirrors (rearview and side mirrors).

No 'tintz' on my windows, so i've ended up just leaving the OEM motorized sunshade in the Up position. Largely solves the rearview issue.

[mdgrwl]

I think it dims enough... but to actually trigger the dim takes some work. It has to be completely dark outside... hate that.

[The.Wizard]

I believe the auto dim mirrors have been designed with xenon headlights in mind. Due to the nature of their intensity a new filtering system has been incorporated into the mirror which is also supposed to react in way which is kinder to the eyes in it's operation.

[priceprince]

Works great for me, but this is my first luxury car, so I'm not used to cool stuff like auto dimming mirrors. :)

[S4Tokyo]

The standard design spec on those electrochromic mirrors, for reflectivity, is to operate between 70% refelctiveity (they can't achieve higher than that) and as low as 10% reflectivity (when there is max glare from headlight in rear).

Typically it's designed for non-privacy glass setup i.e. it uses rearward and forward facing photo sensors, comparing the difference on light input on two sensors and through an algorithm changes dimming level of mirror cell. IF you have dark tint on rear glass then (although not supposed to have significant effect), it can effect performance of dimming. Alternatively IF you have added any Drive Recorder, Antenna device or other in the area of Inner Mirror, which interferes with line of sight of forward facing light (photo) sensor, then that also will effect performance / speed and or amount of change of dimming.

It would be extremely unusual that there would be variation in build of Electrochromic Mirrors, which would perform differently than spec and intention - from a design / manufacture standpoint. There would be 'end of line' assembly test equipment that checks performance before packaging and shipping to vehicle manufacturer. Whether there might be external factors impacting the light photo sensors is another question. Alternatively, it could be that certain owners expectation of dimming speed has higher expectations than others ……which is very possible?:-( [If situation needed to change from max 70% reflectivity to say min 10% reflectivity then you should observe that change in couple / few seconds. IF car is already in light environment where, 'say', Mirror is at 50% reflectivity state and suddenly it needs to change to 30% reflectivity state, then the impact to Drivers sensing of dimming action won't be so drastic / so noticeable ].

Not sure that helps in any way to explain what you observe?

To some other members comment, maybe standard Prism Mirror with Day/Night toggle is all that is needed. Certainly there are many that think so:-)

Compared to my B5 S4 and other vehicles I have, the auto dimming rearview mirror in the B8 S4 sucks.

It takes a long time to dim, and it doesn't dim that much. It won't dim at all during dusk/twilight and only when it's total dark

Is it just me or are they all like that?

[Cooper993]

The standard design spec on those electrochromic mirrors, for reflectivity, is to operate between 70% refelctiveity (they can't achieve higher than that) and as low as 10% reflectivity (when there is max glare from headlight in rear).

Typically it's designed for non-privacy glass setup i.e. it uses rearward and forward facing photo sensors, comparing the difference I light input and through algorithm changing darkness of mirror cell. IF you have dark tint on rear glass then (although not supposed to have significant effect), it can effect performance of dimming. Alternatively IF you have added any Drice Recorder, Antenna divide or other on area of Inner Mirror, which interferes with line of sight of forward facing light (photo) sensor, then that also will effect performance / speed and or amount of change of dimming.

It would be extremely unusual that multiple Electrochromic Mirrors would perform differently than spec and intention - from a design / manufacture standpoint. Whether there might be external factors impacting the light photo sensors is another question. OR, it could be that certain owners expectation of dimming speed has higher expectations than others ……which is very possible?:-( [If situation needed to change from max 70% reflectivity to say min 10% reflectivity then you should observe that change in couple / few seconds. IF Car is already in light environment where, 'say', Mirror is at 50% reflectivity state and suddenly it needs to change to 30% reflectivity state, then the impact to Driver of dimming action won't be so drastic / so noticeable ].

Not sure that helps in any way to explain what you observe?

To some other members comment, maybe standard Prism Mirror with Day/Night toggle is all that is needed. Certainly there are many that think so:-)

I like the auto dimming mirror in my other cars including the B5. It just seems that the algorithm/formula they used for the B8 is not very good.

I have no extra tint or other things blocking the areas around the mirror. I think the replies here confirm it was "designed that way".

Since I'm still under warranty, may take it in to have it checked out.