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: Pcm configuration
1. Connect the WDS to DLC-2.
2. Set up the WDS (including the vehicle recognition.)
3. Select Module programming.
4. Select Programmable module installation.
5. Select PCM and perform procedures according to directions on the WDS
screen.
Note
If PCM CONFIGURATION is successful, the PCM ...
Mazda 6 Owners Manual: Condenser removal/installation
1. Disconnect the negative battery cable.
2. Discharge the refrigerant from the system. (See RECOVERY.) (See CHARGING.)
3. Remove the shroud panel. (See SHROUD PANEL REMOVAL/INSTALLATION.)
Caution
If moisture or foreign material enters the refrigeration cycle,
cooling ability will be lower ...