Auto Dim Rear View Mirror

marcm · 07-27-2010, 08:38 AM

Does anyone know if there is a way to force the Auto Dim Rear View to dim ?

Sometimes its necessary to dim it like when you have a christmas tree Audi behind (God those LEDs are bright

) or a motorbike that insists on having his/her full beam on.

I've thought of taking it off and modifying the sensor input with a switch so that it loads it to force the mirror to dim. Anyone else looked at it or have a problem ?

doughboy · 07-27-2010, 09:24 AM

IMO it needs an OFF button (like VAG cars) so you can switch off the dimming feature. With a manual mirror I would never dim it in town as there's no need, so I wish you could turn off the BMW dimming.

It should auto-dim to a variable level according to the light from behind versus the ambient light level. It can take a second or so if a very bright light comes on suddenly behind you, I know mine does anyway.

I find if anything it dims too much, especially in town, so much so that you can't see any unlit objects - like pedestrians or cars from side on or police cars etc.. You just end up with a black mirror with two headlights in it.

BTW - same goes for side mirror auto dimming too.

marcm · 07-27-2010, 09:33 AM

yeah but when its bright daylight it doesnt dim at all even if the lights behind are on full beam. Works beautifully at night/dusk though.

creepy coupe · 07-27-2010, 09:48 AM

Get some rear tints, my mirror hasn't dimmed since fitting mine

marcm · 07-27-2010, 09:55 AM

Maybe I should clarify the problem is during the day, in daylight. At night it is perfectly fine.

doughboy · 07-27-2010, 10:02 AM

I think the dimming doesn't work unless the headlights are on?

Even with your lights on I'm sure the dimming won't work either unless the ambient light level is 'dark' enough to warrant it. Broad daylight should not result in any dimming IMO as the difference between the ambient light and the 'annoyance' light won't be enough.

Never notice the audi DRLs being too bright except at dusk. From next year (or 2012?) all cars in EU will have to have permanently on DRLs....just like Scandinavia.

marcm · 07-27-2010, 11:37 AM

I must be uber sensitive to bright lights. Even the drl on the lci coupe I think are too bright.

parapaul · 07-27-2010, 12:18 PM

Quote:

Originally Posted by doughboy

I think the dimming doesn't work unless the headlights are on?

Even with your lights on I'm sure the dimming won't work either unless the ambient light level is 'dark' enough to warrant it.

I think this is correct.

shane55 · 07-27-2010, 06:30 PM

There are two photo electric resistors in the mirror, one on the mirrored side facing traffic coming from behind and one on the back of the mirror, When both values read the same level of light no dimming is performed, night or day. When one reads higher or lower than the other the mirror is forced into dimming...and varied depending on how dark or how bright the light is!...so during the day if you want your mirror dimmed...put your finger around the front of the mirror and feel the sensor...cover it and the mirror dims....get some black tape and you now have a dimmed mirror!

marcm · 07-29-2010, 06:54 AM

Quote:

Originally Posted by shane55

There are two photo electric resistors in the mirror, one on the mirrored side facing traffic coming from behind and one on the back of the mirror, When both values read the same level of light no dimming is performed, night or day. When one reads higher or lower than the other the mirror is forced into dimming...and varied depending on how dark or how bright the light is!...so during the day if you want your mirror dimmed...put your finger around the front of the mirror and feel the sensor...cover it and the mirror dims....get some black tape and you now have a dimmed mirror!

I think it also uses the ambient light sensor on the windscreen. I have switch the headlights on in daylight and covered the photo-cell on the back of the mirror and it doesnt dim. However if I cover the photo-cell on the back of the mirror at night the mirror dims, so it uses an additional photo-cell.

I'm going to have to get the missus to sit on the bonnet and cover the sensor and then I can see if it works.

xenon · 07-29-2010, 06:56 AM

Quote:

Originally Posted by shane55

There are two photo electric resistors in the mirror, one on the mirrored side facing traffic coming from behind and one on the back of the mirror, When both values read the same level of light no dimming is performed, night or day. When one reads higher or lower than the other the mirror is forced into dimming...and varied depending on how dark or how bright the light is!...so during the day if you want your mirror dimmed...put your finger around the front of the mirror and feel the sensor...cover it and the mirror dims....get some black tape and you now have a dimmed mirror!

Only if the headlights are on.

misterS3 · 07-29-2010, 07:54 AM

Quote:

Originally Posted by marcm

I'm going to have to get the missus to sit on the bonnet

(since Will is clearly working for a change).....we need photos

Wingco · 08-01-2010, 07:23 PM

Being able to switch OFF the auto-dimming feature in my A3 was very helpful sometimes.

07-27-2010, 08:38 AM	#1
marcm Lieutenant 23 Rep 462 Posts Drives: F25 X3 LCI Join Date: Jan 2007 Location: UK iTrader: (1)	Auto Dim Rear View Mirror Does anyone know if there is a way to force the Auto Dim Rear View to dim ? Sometimes its necessary to dim it like when you have a christmas tree Audi behind (God those LEDs are bright ) or a motorbike that insists on having his/her full beam on. I've thought of taking it off and modifying the sensor input with a switch so that it loads it to force the mirror to dim. Anyone else looked at it or have a problem ?
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07-27-2010, 09:24 AM	#2
doughboy Major General 1578 Rep 8,971 Posts Drives: 2018 M2 Comp 6MT Join Date: Jan 2009 Location: UK iTrader: (2)	IMO it needs an OFF button (like VAG cars) so you can switch off the dimming feature. With a manual mirror I would never dim it in town as there's no need, so I wish you could turn off the BMW dimming. It should auto-dim to a variable level according to the light from behind versus the ambient light level. It can take a second or so if a very bright light comes on suddenly behind you, I know mine does anyway. I find if anything it dims too much, especially in town, so much so that you can't see any unlit objects - like pedestrians or cars from side on or police cars etc.. You just end up with a black mirror with two headlights in it. BTW - same goes for side mirror auto dimming too.
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07-27-2010, 09:33 AM	#3
marcm Lieutenant 23 Rep 462 Posts Drives: F25 X3 LCI Join Date: Jan 2007 Location: UK iTrader: (1)	yeah but when its bright daylight it doesnt dim at all even if the lights behind are on full beam. Works beautifully at night/dusk though.
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07-27-2010, 09:48 AM	#4
creepy coupe Lieutenant General 1825 Rep 13,043 Posts Drives: BMW M340I G20 Join Date: Aug 2007 Location: UK iTrader: (2) Garage List 2015 BMW 435d [0.00] 2009 335i [0.00]	Get some rear tints, my mirror hasn't dimmed since fitting mine
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07-27-2010, 09:55 AM	#5
marcm Lieutenant 23 Rep 462 Posts Drives: F25 X3 LCI Join Date: Jan 2007 Location: UK iTrader: (1)	Maybe I should clarify the problem is during the day, in daylight. At night it is perfectly fine.
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07-27-2010, 10:02 AM	#6
doughboy Major General 1578 Rep 8,971 Posts Drives: 2018 M2 Comp 6MT Join Date: Jan 2009 Location: UK iTrader: (2)	I think the dimming doesn't work unless the headlights are on? Even with your lights on I'm sure the dimming won't work either unless the ambient light level is 'dark' enough to warrant it. Broad daylight should not result in any dimming IMO as the difference between the ambient light and the 'annoyance' light won't be enough. Never notice the audi DRLs being too bright except at dusk. From next year (or 2012?) all cars in EU will have to have permanently on DRLs....just like Scandinavia.
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07-27-2010, 11:37 AM	#7
marcm Lieutenant 23 Rep 462 Posts Drives: F25 X3 LCI Join Date: Jan 2007 Location: UK iTrader: (1)	I must be uber sensitive to bright lights. Even the drl on the lci coupe I think are too bright.
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07-27-2010, 06:30 PM	#9
shane55 First Lieutenant 32 Rep 336 Posts Drives: BMW 330d M-Sport Auto Join Date: Oct 2009 Location: IRL iTrader: (0)	There are two photo electric resistors in the mirror, one on the mirrored side facing traffic coming from behind and one on the back of the mirror, When both values read the same level of light no dimming is performed, night or day. When one reads higher or lower than the other the mirror is forced into dimming...and varied depending on how dark or how bright the light is!...so during the day if you want your mirror dimmed...put your finger around the front of the mirror and feel the sensor...cover it and the mirror dims....get some black tape and you now have a dimmed mirror! __________________ Sapphire Black* Darklines* Black Dakota Leather* Heated Seats* Professional Navigation* Xenons* High Beam Assist* Hi-Fi* USB Audio* DAB* BMW Assist* Sun Protection Glass
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08-01-2010, 07:23 PM	#13
Wingco Private 2 Rep 91 Posts Drives: VW CC GT (2013MY) Join Date: Jun 2008 Location: UK iTrader: (0)	Being able to switch OFF the auto-dimming feature in my A3 was very helpful sometimes. __________________ GONE: 320d Editions SE - SG; Lemon Dakota; V-spokes style188, Hifi Loudspeaker, 6FL, Auto Lights/wipers. HELLO: VW CC GT Deep Pearl Black; Desert-Beige/black leather.
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