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: Intake-air system removal/installation
Warning
When the engine and intake-air system are hot, they can badly
burn. Turn off the engine and wait until they are cool before removing the
intake-air system.
Fuel vapor is hazardous. It can easily ignite, causing serious
injury and damage. Always keep sparks and flames away from ...
Mazda 6 Owners Manual: Instrument cluster input/output check mode
Note
In this mode, it is possible to check the items in the following
chart.
Diagnostic Trouble Code Chart
Note
Diagnostic trouble codes which are not listed may be indicated,
but they cannot be inspected.
The diagnostic trouble codes are displayed in numerical order.
(While ...