Switch on mirror

I am wondering what the switch on the mirror is for. I have done a little looking, but have not come up with much. Is it to dim the mirror for when bright lights are behind you, or is it for the twilight sensor for the headlights?

you answered your own question man YESSSSSSSSSSSSS thats the dimming switch

I don't know if mine don't work well or these dimmers don't work well in general, but they don't work like my bonneville dimmer did. The bonneville dimmed very quickly when set to high and I could really see a difference between on and off. The Riv is harder to tell. Is this normal?

Mine works pretty well. Gets green & dim when lights are behind.

it depends on how much your windows are tinted b/c the sensor is on the rear view mirror. mine worked faster and better before i had the windows tinted, it still works great now and dims just fine, but it takes a little bit more lights to make it kick on

But when you think about it, that might not be an issue. It's all relative, because in the end the sensor needs the same amount of light in order to do its job, so it still works, just doesn't need to as much because there's less light coming in.