Auto-dimming mirror modification idea.

I may be in minority here, but I am pretty annoyed at my auto-dimming rear view mirror functionality on my Gen 2. I prefer the dimming to be constant when I want it. I don't like it to dim and undim as I drive through various traffic and lighting patterns. Call me old school, but I really like the old mechanical rear view mirrors with a slightly less reflective coating at a different angle and a mechanical switch that changed the angles between the two settings. That works great and changing that to a complex electronic/optical solution, IMO, is one of those things we do just 'cause we can, not because it's better. I understand that if tuned perfectly to the user, the auto-dimming mirror may be great, but how many people are alike in how they like it to operate? For me, the hysteresis of the system is all wrong. I find that the mirror does not dim quickly enough and goes out of dim too fast. I get irritated by the headlights from the back of me a lot with this system. It's not totally useless, but it is way less effective (for me) than a regular old mechanical dual layer setup (and so much more complicated!). My ideal situation would be for the mirror to dim when I tell it to and stay dimmed until I tell it to undim. I am totally okay with fully dimmed mirror in the dark. I can still see most of what I need to see in it. And when there is a car that suddenly appears I am not blinded by its lights until such time as the auto-dimming system decides to do its job.

So, my theoretical solution is this. I would like to replace the light sensor (photo diode, I imagine) of the dimming circuit with an on-off switch or a button to simulate full brightness signal from the sensor all the time. This way the system will just keep the mirror dimmed. When I switch that off it can either go back to being automatic or just be un-dimmed at all times.

I wonder if anyone has done that? Looked inside the auto-dimming circuitry? Am I the only weirdo that is bothered by how it works?

I really like the garage door opening feature of the mirror or I would just swap it out for a conventional mirror.

 

Yes, I am not sure why manufacturers even go there. It's not like the conventional mirror that has been working great for over 50 years is in need of improvement. I hate when technology is used just because and not for a good reason. I am very much a techie and an engineer, but also of the mind that the best solution is always the simplest.

I guess I need to find a used mirror to play with as I really don't want to mess with mine for experiments. I can totally see the technical solution that should, in theory be very simple. I would need to figure out the circuitry of the light sensor and replace it with a switch that basically simulates the condition under which the mirror will fully (or partially using a potetiometer to adjust) dim. Right now there is a photo diode sending signals to the "brain" of the dimming circuit. I want to replace the photo-diode with a switch or a knob to adjust the dimming level. That way I can just leave it in that position until I decide to undim it. I find it very presumptuous on the part of Toyota to know when I want the mirror dimmed and how much.

 

It can dim almost to the same level as the manual, but almost never does because someone at Toyota decided what you like. That's my main problem with the whole thing. It's a stupid use of a lot of technology to solve a problem that has been successfully solved decades ago and does not need improvement.

If you manage to get it to dim (and stay dimmed) to the max, you be okay with it, but good luck with that. I would have changed it out for the conventional mirror, but I would miss the homelink. Really like that. So I am going to try to rig something up to manually dim the electric mirror to my liking. I think it's probably not super complicated, but I may be wrong.