the autodim rearview mirror brightens when you put the gear in reverse.
what a nice design.

update: for all of you going to try it
I notice it when autodim is on in my garage so the front sensor of the auto dim is sensing low light and the rear is sensing high light so the mirror dims.
when I put in reverse, it brightens.

so if you dont have a garage what you can simulate this situation is to put in neutral cover the front sensor witch is behind the mirror casing facing the front of the car. the mirror should start to dim, then you keep that and put gear in reverse, it should be come bright.

 

Never noticed it, I will have to test this hypothesis!

 

This should be in The Little Things

And I'm going to go try it!