Found this by chance, thought it good to share.
Press the Voice Command button on your steering wheel.
Say" Display Day Mode" to switch the NAV display to bright background.
Say" Display Night Mode" to switch the NAV display to dark background.
Say" Display Auto Mode" to switch the NAV display automatically as detected by the day/night sensor.
Say" Display Help" to confirm I listed the commands correctly LOL!

Press the Voice Command button on your steering wheel.
Say" Display Day Mode" to switch the NAV display to bright background.
Say" Display Night Mode" to switch the NAV display to dark background.
Say" Display Auto Mode" to switch the NAV display automatically as detected by the day/night sensor.
Say" Display Help" to confirm I listed the commands correctly LOL!