dim-less self-dimming rearview mirror

[Ares]

My rearview mirror does not adequately dim. If I turn it off at night there is little difference and always glare from other vehicles.

From what I can tell, the mirror uses an ambient light sensor up front, and rear light sensor. It auto-dims based on the difference. The manual said it disables in Park or Reverse.

So I tested it at night with a LED light (in my dark driveway with the trans in D, car stopped). I could see it dim very slightly, LED shining in the rear sensor. So it works, just not very well. Is there a way to reset the system/sensitivity?

 

[jaydhall]

I have the same question and results. So far I have not seen anyway to improve the sensitivity. Hopefully some one might be able to assist us!

 

[afarfalla]

My rearview mirror does not adequately dim. If I turn it off at night there is little difference and always glare from other vehicles.

From what I can tell, the mirror uses an ambient light sensor up front, and rear light sensor. It auto-dims based on the difference. The manual said it disables in Park or Reverse.

So I tested it at night with a LED light (in my dark driveway with the trans in D, car stopped). I could see it dim very slightly, LED shining in the rear sensor. So it works, just not very well. Is there a way to reset the system/sensitivity?

I had no problem with mine? it was dim all the time

 

[tdiatlast]

Either of you posters have after-market tinted windows?

 

[VeeDubTDI]

Some 35% tint will fix that.

 

[Ares]

I have 35%, which is not dark. The glare was worse before the tint. Window tint never caused a problem on my other vehicles.

 

[compu_85]

Sounds like it might be broken. The mirror in our Jetta and Passat (and my Audi before it) all get quite dark.

-J

 

[VeeDubTDI]

Sounds like it might be broken. The mirror in our Jetta and Passat (and my Audi before it) all get quite dark.

-J

Without the tint the Passat would definitely not be dark enough (in my opinion).

 

[in2dwww]

I have the same issue. My mirror was replaced because I complained about a warped view out of the mirror. I blamed it on a defective rear window (an issue I'm not going to bother to elaborate or justify to this board). Even after a new mirror, I still have a warped vision out the rear window and the mirror does not dim worth a Jack **** dime. But this is only a minor inconvenience as it is eclipsed by so many more issues that keep rearing their ugly heads.

 

[VeeDubTDI]

Yeah the back glass isn't optically perfect and will create a slightly distorted view.

 

[Salsaman06]

Mine dims significantly even after the recent tint job I had done.

 

[jaydhall]

I do not have any window tinting.

 

[Ares]

Is there anything in the VCDS pertaining to the mirror?

 

[VeeDubTDI]

Nope.

 

[jaydhall]

I just tested my mirror while parked in my garage. I can see that there is some dimming but not as much as I would like. However, that being said, I put a flashlight on it and when it is dimming I can ALMOST stand the glare. When I turn the mirror off, the glare causes pain.

So, I know I am sensitive to light, I guess a normal person would not mind this. Hazel eyes sometimes are a pain...

Sure wish I could adjust this little devil.

 

[VeeDubTDI]

A darkness adjustment would be fantastic - but I have yet to see an auto-dimming mirror with that option.

 

[scurvy]

The auto-dim mirror in our Mazda 5 fails to get adequately dim while driving in the city (which is only about 95% of the night driving we do...) and I've played around with it a bit. If the mirror is the same kind as in your Passats, it relies on a forward-facing light sensor as well as the rear-facing sensor. When the light differential becomes biased toward the rear of the car past some preset amount, it begins to dim.

So make it work in your favor - cover the front sensor temporarily with your finger and watch the mirror go jet black quickly. If that test works for you, get some 5% limo tint and put a small piece on the front light sensor, effectively re-biasing the system to be more sensitive to rear sources of light.

Then again, I don't have a NMS so I can't vouch that yours works the same way as my fünf.

 

[compu_85]

The NMS mirror would respond to that front tint method. Look on your Mazda, the mirror is probably made by Gentex, they also make the VW mirror (and most auto dimming mirrors).

-J

 

[jaydhall]

Stole my plan! Though I was going to try it first with a piece of black tape just to see if it did anything. Thanks for the idea! Would be wonderful if it works.

 

[VeeDubTDI]

Black tape will make your mirror dim in the day - just FYI - maybe it won't bother you.

 

[Lightflyer1]

Didn't work with mine just now.

 

[jaydhall]

OK. I have done my playing with the sensor. I really do not see an increase in the function of the mirror. I go to work at 0 dark 30. Covering the front sensor did not seem to improve the amount of dimming. Turning it off DID make it way worse. So, it still comes down to the fact that I wish I could make the mirror dimmer. I at least proved to myself for sure this morning that it DOES dim a bit. Takes it from horrible to annoying. My wife of 40 years says I am annoying. Hmm.... I wonder if this is her revenge!
Sure wish my VagCom could talk to the mirror and reason with it!

 

[scurvy]

Maybe your mirror is actually not functioning correctly?

Find a local member with a similar car and see if y'all can do some A/B testing after dark.

FWIW the auto-dimming mirror in in our fünf takes a while to get very dark - it goes through several shades of 'green' before it goes 'black'.

 

[VeeDubTDI]

You could always put window tint on the mirror itself if you don't want to tint the windows on your vehicle.

The mirror is functioning as good as it's going to in stock form - they just don't get dark enough for some folks. Covering the sensor in the front won't make it get any darker than what it's already doing in the middle of the night.

You could experiment with the mirror to see what the voltage curve actually is for various darkness levels. Perhaps the mirror doesn't max out at 14v or whatever and you can change a resistor to make it get darker. This will obviously require taking the mirror apart and measuring some things with a multi meter.

 

[scurvy]

Covering the sensor in the front won't make it get any darker than what it's already doing in the middle of the night.

True - covering the front sensor will only make it get dark more quickly and/or make it more sensitive to light coming into the rear of your car. It does not change how dark the mirror gets.

Stronger tint on the rear window or indeed tinting the mirror itself are two options.

 

[rustycat]

True - covering the front sensor will only make it get dark more quickly and/or make it more sensitive to light coming into the rear of your car. It does not change how dark the mirror gets.

Stronger tint on the rear window or indeed tinting the mirror itself are two options.

Fiip up style sun shades ought to work. Amber, green, grey, hmmmm I think I'm inspired.