2004 Toyota Avalon Navigation Manual - Page 706

AVALON_Navi_U (L/O 0307) When the headlight switch is at "ON" position, the screen changes to the day mode or night mode. To display the screen in the day mode even with the head light switch on, select "DAY MODE" switch on the adjustment screen for brightness and contrast control. If the screen is set in the day mode with the headlight switch turned to on, this condition is memorized in the system even with the engine turned off. 114