Jay Honeck wrote:
Gee, I'm surprised Garmin doesn't have a better dimmer circuit. My
AvMap has a dimmer circuit that tones it all the way down to nuthin'.

In fact, we actually thought the unit was broken one day when it
wouldn't "power up." It turned out we had dimmed it so much the
night before that we couldn't see it in the daylight!

That's likely why it has a minimum brightness setting - it keeps the
service calls down.