Rear view mirror auto dimming/anti-glare test ?

**b206** · 10-11-2013,02:35 PM

Hello,
Now that winter is starting to set in I'm noticing a view issues with my 2009 A4 - the main problem being the auto dimming/anti-glare rear view mirror and side mirrors which don't seem to dim.
I have privacy glass which I understand can cause problems - but how do I test the rear view and side mirrors ? I've tried flashing a light at the mirror and covering the rear sensor up but nothing seems to activate the anti-glare.

Any tried and tested methods ?

Cheers.

**Guest 2** · 10-11-2013,02:37 PM

How do you know you have autodimming mirrors? I know they came with RVM but the wing mirrors themselves were an optional extra I think.

Do your wing mirrors have an line running along the edge of the glass?

Welcome to VWAF

**b206** · 10-11-2013,02:40 PM

Hi - I checked the option codes which say I have auto-dimming and heated side mirrors. Also have the line around the edge.

**Guest 2** · 10-11-2013,02:47 PM

I assume the green light is on when you're doing the test on the rvm?

Is the privacy glass factory fit or aftermarket film? Could you not ask someone you know to drive behind you with their full beam on at night?

A fault scan would show if anything is wrong.

**b206** · 10-11-2013,03:10 PM

Yep, green light is on - factory fitted tint.
When driving at night it doesn't seem to work when cars are behind, I've been told the tints can prevent enough light hitting the sensor so the mirrors don't dim to the same degree as vehicles without tints.
To be honest the rear view mirror isn't too bad as the tints block most of the light - would be useful if I could get the side mirrors working though.

The rear mirror has a sensor at the back which I'm guessing tells the mirror when its dark - it looks like there is a sensor to the right of the on/off button which must detect headlights from behind. I was hoping you could block the rear sensor (which will tell the system its dark) and shine a light into the front sensor (headlights), but it looks like the system is difficult to fool?!

**Guest 2** · 10-11-2013,03:19 PM

They only dim when the car behind has full beam on, dipped beam is fine and it won't pick it up.

I noticed this on the loan A8L I had which had the wing mirrors too and they didn't dim until the full beam from the car behind was on.

**AGW82** · 13-11-2013,11:17 PM

I have factory tints and dimming rvm + folding/dipping wing mirrors. I also had this on my A6 C7 and my previous A4 B8 Avant. All have responded the same, which is quite sporadic in when it chooses to dip the rvm and mirrors. As Chris has said people using high beam still definitely trigger it, even with tints, but the system will also work with lights on normal dipped beam but it seems to be more hit and miss.

I understood (but could be wrong) that if you have factory tints the light sensors are adjusted to compensate for the tint.. I've never had a car without tints so I'm not sure how effective the system is without.

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**b206** · 14-11-2013,11:15 AM

I had a long drive last night and my mirrors do auto dim, but as AGW82 says above, its sporadic!
Depends on how left/right the car is behind and how close. If you are in a queue at lights they will dim, if they drop back a few feet they dont. If you are on a long stretch of road and the car behind is way back, they will dim - but don't seem to dim in-between!

Anyway when they do work its a good feature to have - shame they didn't think about moving the sensors outside/back, would be far more reliable.

**sportq** · 14-11-2013,02:26 PM

Originally Posted by AGW82

I understood (but could be wrong) that if you have factory tints the light sensors are adjusted to compensate for the tint..

This would be excellent if it turns out to be the case as there's a chance that it's something that can be tweaked in VCDS. Anyone with EKTA access able to confirm if the dipping rear mirror is the same on tint and non-tint vehicles?

I'll ask on the Ross-Tech VCDS mailing list if the mirror is codeable.

Peter

**ScottyUK** · 15-11-2013,01:34 AM

From what you've said it sounds like a problem. If the interior mirror dips so should the wing mirrors. However in case I've misunderstood :

I've posted this a few times in the past but here goes :

The mirror sensor is not tuneable for brightness.

I've got privacy glass and I told Audi that it meants it doesn't tint as early as it should. I got told to take it to my dealer and request they investigate and if they agree to raise it as an issue. I did and they did.

Audi came back saying I was right. They paid me the full value of the folding / dimming mirros back - £150 if I remember correctly.

I did suggest they put something in the catalogue to say if you have privavly glass it doesn't work as well but they never have.