The High Beam Control System (HBC) operates to switch the headlights automatically between high and low beams after the ignition is switched ON and the headlight switch is in the AUTO and high beam position.
The High Beam Control System (HBC) determines that it is dark based on the brightness of the surrounding area. At the same time, the High Beam Control System (HBC) indicator light (green) in the instrument cluster illuminates.

NOTE
When the vehicle speed is less than about 20 km/h (12 mph), the High Beam Control System (HBC) switches the headlights to low beams.
High Beam Control System (HBC) (Some models)
Manual SwitchingMazda 6 Owners Manual: Dsc hu/cm removal/installation
Caution
When replacing the DSC HU/CM, configuration procedure must be done
before removing the DSC HU/CM. If configuration is not completed before
removing the DSC HU/CM, DTC B2477 will be detected.
Do not drop the DSC HU/CM. Replace it if it is subjected to an
impact.
1. Configura ...
Mazda 6 Owners Manual: Cruise Control Function
While this function is operating, the headway control operation is canceled and
only the cruise control function operates.
The vehicle speed can be set more than about 25 km/h (16 mph).
Use the cruise control function on expressways and other highways which do not
require a lot of repeated acc ...