[agent_orange]

As has been mentioned on a few other threads on here over the years, BMW dropped the electrochromatic auto-dimming on the passenger side external mirror on most models around 2018.

For me this was only a minor annoyance on my '21 M2C since I don't drive it much at night. (too much damaging wildlife, from bugs to deer)
But because I like retrofits and a challenge, I decided to figure out how to get the auto-dimming on the passenger side, something I'm not aware of anyone having done on the F87 C/CS yet.
Plus my 2014 F25 X3 daily beater has 'triple dimming'.

The dimming glass is required, but there is no wiring and connector for the dimming function.
Checking the ISTA wiring diagrams and photos of other mirrors connectors seems to show that they all had the same 5 pins and that the control of the dimming, mirror position motor and fold motor was all done over the one-wire LIN-bus.
It seemed to be the control module in the mirror that needed changing to one that had the extra wires for the dimming.
Almost pulled the trigger on a new surplus stock F20/F30 mirror control module, but checking photos they are a different physical shape to the F8x M mirror modules.

Because my car is RHD, the passenger mirror is the left side, and the modules are left and right specific, but not RHD or LHD specific.
So ended up buying a used LHD M2C drivers side (left) mirror from the USA on eBay for reasonable money (US$150) due to missing the glass, cap, and being a bit dirty and scratched, just as the donor for the module and to practice taking apart the mirror.

Removing the stock mirror from my M2C, dismantling it, and swapping the module was fairly straightforward.
Removing just the speaker/tweeter from the inside of the door was a bit of a pain, so ended up taking the whole door panel off which wasn't difficult.
Also couldn't get to the connector for the fold motor inside the mirror as I couldn't figure out how to remove the front plastic body section even having a donor to be rough with, so just cut, soldered, and heat-shrinked those two wires.

It all went to plan despite a few unknowns, and all functions work perfectly without any coding required.

Donor US M2C left side mirror with wiring and white connector for dimming in addition to the two black heating connectors:


3 bolts attaching the mirror:


Control module of my original non-dimming mirror:


Original non-dimming module left, donor dimming module right:
Note the extra wires coming out of the left side, and they are potted-in rather than being on connectors on the module.


Original non-dimming glass left, new dimming glass right:


For anyone else wanting to attempt this, you will need the module for the correct side left or right, from an F80 M3, F82/83 M4, or F87 M2C or CS, with the dimming, and with or without power fold, and lane change warning to suit your car. Will probably have to buy a complete mirror as the donor like I did.

And also the dimming and heated glass if the donor mirror doesn't come with it.
The Euro aspheric version to suit what my Australian car came stock with is either 51168059567 left or 51168059568 right, which I can recommend buying new from Cars245.
If you are in the US you can either get the right side dimming flat glass again if donor mirror doesn't come with or you find just the module, or use the opportunity to upgrade both sides to the Euro aspheric.

[inTgr8r]

Nicely done!

I don't recall ever driving my car at night, so didn't realize this function was missing

[hlm2c]

You wouldn't happen to have the part # for the control module for dimming mirrors on the right side like on RHD vehicles would you?

[agent_orange]

Originally Posted by hlm2c

You wouldn't happen to have the part # for the control module for dimming mirrors on the right side like on RHD vehicles would you?

No, but after unsuccessfully scouring the internet and eBay for a photo of a right side mirror with cap removed that was clear enough to show the module part numbers, I did my part for this community and took the glass and cap off my car's right mirror.
Being the drivers side for me, it has dimming and is the part all you guys in LHD countries need for this retrofit.

LEFT side module with dimming required for RHD cars: 8053171
RIGHT side module with dimming required for LHD cars: 8053172
These numbers are possibly prefixed with 5116 in front of them, but aren't available seperately from a dealer.

Right side modules have orange stickers vs white stickers for the left.
They are physically identical and I'm pretty sure the only difference is the coding inside to tell it which side it is to respond to LIN-bus commands for that side. Software version numbers seem to support that theory.

[ZPrime]

Originally Posted by agent_orange

If you are in the US you can either get the right side dimming flat glass again if donor mirror doesn't come with or you find just the module, or use the opportunity to upgrade both sides to the Euro aspheric.

FWIW, stock passenger / right-side glass in the US is already aspheric, hence the "objects may be larger than they appear" warning (by federal mandate) over here. There's absolutely no reason to change the passenger glass for a ROW-spec because you're actually getting a narrower field of view out of that glass (although it would be flat & undistorted on the majority of the glass, and just aspheric on the edge).

I'd be curious to know if they even produce aspheric electrochromic passenger glass for the US (with the warning). For the non-M mirrors, especially... do lower-tier 3er and 4er even have dual-dimming as an option?

[agent_orange]

I don't know exactly what is different with the US mirror glass, maybe it is just the warning.
I based my statement on the fact that US F80/82/83 guys 'upgrade' the mirror glass on both sides to the Euro 51168059567 & 51168059568.
And M2C should have the same mirror glass as those cars.

https://f80.bimmerpost.com/forums/sh....php?t=1277440

Bit of confusion in that thread about whether the 567 and 568 glass part numbers have the dimming function or not, but they definitely do.