That display should dim along with the dash lights.
You do know that there is a control to dim the dash lights......right ??
It only works when the headlights are ON.....and/or it is dark out, depending on the model.
The display dims very slightly, bit not enough for my liking. I'm trying to find a parted-out radio either on ebay or a junkyard to experiment with flipping the LCD polarizing filter to reverse the display.
There might be something wrong with it. When I am driving I have to turn my down to half way for it helps me view the road better at night. It displays 6 Zeros for full brightness then down to none for least brightness.
2013 Hyundai Elantra Sedan Grey