-3C isn't bad. We are -3F here today.
What 1993 was trying to say is have someone adjusting it up and down in the car while you stand outside the car and look straight down at it. If you see any green then it'* working and most likely the motor to adjust it isn't working.
When I first bought my car, the person had it dimmed all the way down to zero and adjusted all the way down. It took me moving around in the seat searching for it to see it..then the adjustment motor didn't want to move at first.
These units don't really ever have issues. If you think it'* the unit though, I have two spares and could sell you one cheap.
00 Regal GS: All kinds of cool stuff.