Intermittent auto dimming mirrors

sebringsc · 10-10-2015, 08:23 PM

I have a 2011 335 with auto dimming mirrors, both side and rear however it seems as though they work intermittently for reasons unknown. I can't seem to figure out if there is something that happens randomly that makes them work and I haven't noticed that they work on a regular intervals. I bought the car used in June so I have no clue the history of this problem.

Any suggestions on where to start checking for problems?

Thanks

VTECaddict · 10-11-2015, 12:54 AM

They only work when there's a bright light behind you at night, and it dims to varying degrees, its not just on and off. The bright light has to hit the sensor on the middle top of the rearview mirror.

sebringsc · 10-11-2015, 08:05 AM

Thanks for the explanation. Perhaps I have noticed it does with better when cars are closer which works explain the proximity effect of the sensor.

10-10-2015, 08:23 PM	#1
sebringsc Private 7 Rep 58 Posts Drives: 2011 335i xdrive Join Date: Jun 2015 Location: lake villa, IL iTrader: (0)	Intermittent auto dimming mirrors I have a 2011 335 with auto dimming mirrors, both side and rear however it seems as though they work intermittently for reasons unknown. I can't seem to figure out if there is something that happens randomly that makes them work and I haven't noticed that they work on a regular intervals. I bought the car used in June so I have no clue the history of this problem. Any suggestions on where to start checking for problems? Thanks
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10-11-2015, 12:54 AM	#2
VTECaddict Where'd my VTEC go? 481 Rep 6,067 Posts Drives: 06 330i 6MT Join Date: Mar 2009 Location: Seattle, WA iTrader: (4)	They only work when there's a bright light behind you at night, and it dims to varying degrees, its not just on and off. The bright light has to hit the sensor on the middle top of the rearview mirror. __________________ AW/Terra \| ZSP \| ZPP \| ZCW \| iDrive \| CA Mods: BC BR coilovers \| Blacklines \| M-tech rear \| dual exhaust \| M3 steering wheel \| BMW SSK \| ZHP shift knob \| High-kick CF spoiler \| NBT Retrofit M3 front control arms \| M3 rear guide rods \| Manzo rear toe and camber links \| Monroe rear shock mounts \| Varrstoen ES1 19x9.5+20 Front, 19x11+25 rear
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10-11-2015, 08:05 AM	#3
sebringsc Private 7 Rep 58 Posts Drives: 2011 335i xdrive Join Date: Jun 2015 Location: lake villa, IL iTrader: (0)	Thanks for the explanation. Perhaps I have noticed it does with better when cars are closer which works explain the proximity effect of the sensor.
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