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: Manifold absolute pressure (map) sensor inspection
Note
Perform the following inspection only when directed.
The following vacuum values are indicated by relative pressure
from the MAP sensor.
1. Connect the SSTs (WDS or equivalent) to the DLC-2.
2. Turn the ignition switch to ON (Engine OFF).
3. Select MAP PID on the SSTs (WDS or equi ...
Mazda 6 Owners Manual: Adaptive Front Lighting System (AFS) (Some models)
The adaptive front lighting system (AFS) automatically adjusts the headlight
beams to the left or right in conjunction with the operation of the steering wheel
after the headlights have been turned on and the vehicle speed is about 2 km/h (2
mph) or higher.
A system malfunction or operation c ...