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: A/c unit removal/installation
1. Disconnect the negative battery cable.
2. Discharge the refrigerant from the system. (See RECOVERY.) (See CHARGING.)
3. Drain the engine coolant. (See ENGINE COOLANT REPLACEMENT.)
4. Remove the dashboard. (See DASHBOARD REMOVAL/INSTALLATION.)
5. Remove the theft-deterrent control module. (See ...
Mazda 6 Owners Manual: Meters and Gauges
Instrument Cluster Type A
Type B
Steering Switch
1 - Speedometer 2 - Odometer, Trip Meter and Trip Meter Selector 3 - Tachometer
4 - Dashboard Illumination 5 - Trip Computer and INFO Switch 6 - Engine Coolant
Temperature Gauge 7 - Fuel Gauge 8 - Outside Temperature Display 9 - Cruise
...