2014 - Mazda6 - Body and Accessories

HIGH BEAM CONTROL (HBC) SYSTEM

Outline

• The high beam control (HBC) system performs automatic switching to low beams only when the forward sensing camera (FSC) installed to the windshield recognizes an on-coming vehicle, a vehicle that is ahead or when traveling through towns and cities to prevent blinding of other vehicles from headlight glare and to assure visibility of drivers.

CAUTION:

• Under the following conditions the ability of the forward sensing camera (FSC) to detect light-emitting objects decreases, which could result in the system not operating normally and the inability to detect on-coming vehicles or vehicles ahead.

• Brightness of moonlight in surrounding area

• Poor visibility due to rain and fog

• Scratches or soiling on the camera lens or windshield glass

• Do not rely solely on the high beam control (HBC) system, and perform the appropriate switching operation based on a visual determination of the conditions.

• If the FSC aiming for the high beam control (HBC) system is not completed, the camera shot angle for the FSC cannot be recorded and the high beam control (HBC) system may not operate. When performing the following servicing, always perform the FSC aiming. Refer to the FSC aiming procedure in the workshop manual.

• FSC replacement

• FSC clip replacement

• Windshield replacement

Function

• With the light switch in the AUTO and HI position and when the headlights are turned on, the forward sensing camera (FSC) automatically switches to low beams when it recognizes a light-emitting object (on-coming vehicle, vehicle ahead, town and city streets).

• Refer to "FORWARD SENSING CAMERA (FSC)" for details on the forward sensing camera (FSC).

Setting function for control order of precedence

• If several light-emitting objects are recognized (on-coming vehicles, vehicles ahead, town/city streets), control is conducted according to the following order of precedence.

• Closest on-coming vehicle

• Closest vehicle ahead (no on-coming vehicles)

• Traveling through towns and cities

System conditions display function

• The forward sensing camera (FSC) displays system conditions using the HBC indicator light (green), HBC warning light (amber), and LCD in the instrument cluster (type A).

Structural View

System Wiring Diagram

Block Diagram

Operation

Low beam switching operation

Operation condition

• With the light switch in the AUTO and HI position and when the headlights are turned on, the headlights are switched to low beams when any of the following conditions are met:

• On-coming vehicles, vehicles ahead, town/city streets are recognized.

• Vehicle speed is 20 km/h {12 mph} or less.

• When the forward sensing camera (FSC) recognizes a light-emitting object (on-coming vehicles, vehicles ahead, town/city streets) or detects a vehicle speed of 20 km/h {12 mph} or less, it sends a headlight low beam switching request signal to the front body control module (FBCM).

• When the front body control module (FBCM) receives the headlight low beam switching request signal from the forward sensing camera (FSC), it turns the headlight HI relay off.

• When the headlight HI relay turns off, energization to the high-beam solenoid is cut and the shade rotates.

• When the shade rotates, high beam light is blocked, and only low beam light is illuminated.

High beam return operation

Operation condition

• If the following conditions are met, the headlights are switched to high beams.

• If vehicle speed is 30 km/h {19 mph} or more and on-coming vehicles, vehicles ahead or street lights are not recognized.

On-coming vehicles

• If a recognized on-coming vehicle moves away from the camera range, the forward sensing camera (FSC) sends a headlight high beam switching request signal to the front body control module (FBCM).

• When the front body control module (FBCM) receives the headlight high beam switching request signal from the forward sensing camera (FSC), it turns the headlight HI relay on.

• When the headlight HI relay turns on, the high-beam solenoid is energized and the shade rotates.

• When the shade rotates, the blocked high-beam light is illuminated forward, and the headlight switches to high beam.

Vehicle ahead or town/city streets (street lights)

• If a recognized vehicle ahead moves away from the camera range, or town/city streets (street lights) are no longer detected in the camera range, the low beams are maintained for a certain period of time.

• If a vehicle ahead or town/city streets (street lights) are not detected for a certain period of time, the forward sensing camera (FSC) sends a headlight high beam switching request signal to the front body control module (FBCM).

• When the front body control module (FBCM) receives the headlight high beam switching request signal from the forward sensing camera (FSC), it turns the headlight HI relay on.

• When the headlight HI relay turns on, the high-beam solenoid is energized and the shade rotates.

• When the shade rotates, the blocked high-beam light is illuminated forward, and the headlight switches to high beam.

Forward sensing camera (FSC) loses sight of vehicle ahead which is cornering

• If the forward sensing camera (FSC) loses sight of a recognized vehicle which is cornering, the forward sensing camera (FSC) maintains the low beams until reaching the locus at which the forward sensing camera (FSC) lost sight of it.

• If the vehicle ahead is not detected at the locus at which the forward sensing camera (FSC) had lost sight of it, the headlights are switched to high beams. If the vehicle ahead is detected, the low beams are maintained.

Forward sensing camera (FSC) suddenly loses sight of light-emitting object (on-coming vehicles, vehicles ahead, town/city streets (street lights))

• If the forward sensing camera (FSC) suddenly loses sight of a recognized light-emitting object in the camera range, the low beams are maintained for a certain period of time.

• Depending on whether a light-emitting object is detected or not after the certain period of time has elapsed, the headlights are switched to high beams or the system determines that the low beams are to be maintained.

Fail-safe

• If a malfunction is detected in the system, control is inhibited and the headlights are switched to high beams.