[Canadiesel]

As the title says. My rear view mirror stopped automatically dimming and I'm getting blinded by traffic. The side mirrors are automatically dimming just fine so clearly the light sensors are working, and the test method of covering the front facing sensor proves that as the side mirrors both dim. The frustrating part is that the rear view mirror has stopped switching. There is no visible signs of defects, no bubbles. The car is a 2011 335D. Is this a mechanical or electrical issue? Do I need to replace the mirror?

Thanks

[opjose]

The front facing sensor should be the RLS not the auto-dim sensor.

The auto-dim sensor is on the mirror itself, the small oval.

You can test it with a pen light.

It may be easiest to pick up a used mirror especially if you do not have Homelink nor auto-high beams, since people often upgrade their mirrors and sell their existing units.

[Canadiesel]

Originally Posted by opjose

The front facing sensor should be the RLS not the auto-dim sensor.

The auto-dim sensor is on the mirror itself, the small oval.

You can test it with a pen light.

It may be easiest to pick up a used mirror especially if you do not have Homelink nor auto-high beams, since people often upgrade their mirrors and sell their existing units.

Thanks, yes this is the test I did. Cover front sensor to imitate night time and flash a light in the front sensors on the RVM itself. The side mirrors dim instantly and full dark. The RVM does not change. It has homelink but not auto highbeams.

[opjose]

Originally Posted by Canadiesel

Thanks, yes this is the test I did. Cover front sensor to imitate night time and flash a light in the front sensors on the RVM itself. The side mirrors dim instantly and full dark. The RVM does not change. It has homelink but not auto highbeams.

Please PM me.

[Frankenstein_135]

Reviving this old thread. I have a 2011 (LCI) E91 wagon and am having the exact same issues - the interior rear view mirror does not dim but the side mirrors do. The compass works and homelink should work, though I think it is not compatible with my garage door.

From a quick Google search, I found a suggestion that the interior RVM gets power from the roof module. So I checked fuses relating to that module - #7, 25, 29, 62. All the fuses are good except that there is no fuse for #29. I put one in but the dimming still doesn't work.

Any suggestions or should I just replace the mirror at this point?

[Frankenstein_135]

Originally Posted by Frankenstein_135

Reviving this old thread. I have a 2011 (LCI) E91 wagon and am having the exact same issues - the interior rear view mirror does not dim but the side mirrors do. The compass works and homelink should work, though I think it is not compatible with my garage door.

From a quick Google search, I found a suggestion that the interior RVM gets power from the roof module. So I checked fuses relating to that module - #7, 25, 29, 62. All the fuses are good except that there is no fuse for #29. I put one in but the dimming still doesn't work.

Any suggestions or should I just replace the mirror at this point?

Update - After I replaced the rear view mirror the problem was resolved. Since it was exactly the same model number I did not need to do any coding.