[Mike K]

Hello all,

My car is a 2011 328i e91 with auto dimming mirrors. While both of the side mirrors dim as they should during night driving, the rear view mirror works only every so often. Sometimes, I can wiggle the mirror's adjustment and get it to dim, but other times this doesn't even help either.

The Homelink and compass all work as they should. And no codes either..

I know that the sensor opening on the back of the mirror tells the mirror when it's dark outside, and the oval sensor on the rear view mirror's surface reacts to bright light too to trigger dimming.

I also understand that for my year e91, the Lin Bus instructs the mirror dimming logic as shown in this youtube below. That it's sending data to the side mirrors and also not dimming in reverse, etc.

I'm a handy tech with a soldering iron, and I thought about re-flowing the solder points inside the rear view mirror and check connections etc. I also wonder if the darkening glass just isn't doing it's thing when it gets Lin Bus voltage etc?

But before I dive in there, I thought I would ask this great group if anybody has actually been down this road, and if they have any suggestions? Those big pickup trucks are getting annoying at night at stoplights!

Thanks!

[Mike K]

bump

[Hoody007]

I’m inclined to think there’s something wrong with the mirror itself. You could try the resoldering route, but those mirrors are pretty cheap.

I also have a spare F10 mirror. Should be the same mirror panel, but I think the electronics inside are different. Let me know if you want it.

[Revale]

Hi, I have a related question/issue actually.

I’m currently trying to retrofit a g05 mirror form 2019-2020 year into my 2006 bmw 325i, but the autodim won’t activate. Is the lin bus able to send the same wake commands or is it not cross compatible.

OP posted the YouTube video with the whole simulating the Lin signals but I wonder if that’s the only route.

Thanks for your help!