Just checked my lights again. Rebel is correct regarding the overhead switch. Three positions. Left is Off, Right is On. Center allows the lights to come on when the door is opened. however, this switch hasn't anything to do with the brightness of the dash lights or UConnect Screen.
Dial switch (on dash next to light switch) only has one click on the north end or up position that sets the dash lights and UConnect screen to the brightest position. Anything below this notch dims the same dash lights and Uconnect screen.
The question involves the Set Up withing the Uconnect 5 System. In the Display Setup, you can choose Auto or Manual. In the Auto Mode nothing changes. In most vehicles Auto Mode changes the Radio screen to a darker mode so the driver isn't blinded at night. Anyone who uses Nav at night understands how the screen changes to night mode during night drives. It works much like your cell phone where you have a night screen and a day screen.
You can manually set the screen to be either in Light Mode or Dark Mode and change the brightness with Headlight On or Headlights Off. However, come nighttime the Uconnect Screen doesn't change to night mode.
You would think Auto Mode would automatically change the screen mode to Light Mode during the day and Night Mode during the night, but that would be too simple to an engineer or a programmer.
To override the system I just put in in Auto Mode and selected Dark Screen Mode and turned the dial up to the brightest position past the click. Not the ultimate set up on a $65K truck, but oh well!!