From the GM Upfitter website's PDF:
Automatic High Beam Assist (AHBA)
The automatic high beam assist (AHBA) system operates the high beam headlamps ON and OFF automatically when the system is activated and certain conditions are met. The AHBA system consists of a front camera module that detects light and is able to identify approaching vehicles on an even, straight road at a distance of greater than 0.4 km (0.25 mi). The front camera module analyzes light color, intensity, and movement.
The AHBA system will turn OFF the high beam headlamps when approaching vehicle headlamps or preceding vehicle taillights are detected by the front camera module. AHBA can be deactivated when the headlamp dimmer switch is moved from the neutral position to the high beam or flash to pass positions. AHBA can be reactivated by operating the high beam select switch from the neutral position to the high beam position twice within 2 seconds.
AHBA System Activation
• Vehicle ON
• Headlamp switch placed in the AUTO position
• Headlamp dimmer switch must be in the neutral position
• Outside lighting conditions must be dark
• Vehicle speed greater than 25 mph (40 km/h)
AHBA System Operation
The following are conditions that the AHBA system will turn the high beam headlamps off during operation:
• The system detects approaching traffic headlamps
• The system detects preceding traffic tail lamps
• Ambient light level too high due to towns or twilight situations
• The vehicle’s speed drops below 13 mph (22 km/h)
• Delay
Note: AHBA may not operate properly if any of the following conditions exist:
• Approaching and preceding vehicles lamps are undetectable due to dirt, snow, road spray, smoke, fog, or any other airborne conditions.
• The front camera module is covered with ice, dirt, snow, haze, or is obstructed.
• The vehicle is being driven on winding or hilly road conditions which would make any on coming vehicle headlamps undetectable by the AHBA.
AHBA System Deactivation
• Manually operating the headlamp dimmer switch from neutral to high beam position
• AHBA is deactivated automatically when the front or rear fog lamps are turned ON
AHBA System Indicator
The status of the AHBA system is shown by a green indicator located on the instrument panel cluster. When AHBA is active, the indicator will be illuminated continuously. If the operator deactivates the AHBA system, the indicator will turn off.