Navigation map won't go into night mode

[Contrails]

Anyone else have this problem? My Navigation map will not go into night mode. Of course I checked settings and tried to set day/night mode into night mode, and that doesn't work, neither does it in automatic mode. I recently updated my map data to the latest, and updated my software in hopes that this would work, but they had no effect.
I have made an appointment at my local BMW dealership for a fix. My clock, if that matters, is set correctly. It's annoying to have to turn the brightness way down on the display at night. This issue seems to effect the heads up display brightness, too.

[WWnyc]

Sounds like a sensor on the front grill. That would also adjust the HUD

[tyzer]

do you have the dynamic traffic on, i think this overides day n night mode

[Contrails]

tyzer, you are correct. I turned off "traffic conditions/gray map" and the map goes into night mode just fine. So, I immediately consulted the manual and read about it.
Just part of my learning curve on the car. This is also my first BMW, so I'm new to iDrive. I've read about 3/4 of the manual now, but I had not read those pages yet.