Smart Lighting

Different lighting technologies can be mounted individually, or together, to form comprehensive adaptive lighting systems, otherwise known as smart lighting. Automatic headlight leveling systems ensure that the headlights are always correctly aligned, regardless of the load the vehicle is carrying. When a vehicle is loaded, the suspension settles, changing the angle of the headlights to the road. The resulting angle can cause glare into oncoming traffic. Autoleveling headlights use a sensor to monitor the angle of the vehicle to the road Figure 39-26. This information is then used to automatically adjust the headlights. They adjust up or down so the headlights always stay correctly adjusted. In this system, the load sensors provide information to a control module that operates servomotors installed on the headlights, causing the headlights to tilt up and down.

Another function of adaptive headlights is the ability to adjust the length of the headlight beam based on the distance of oncoming traffic. In this system, a dash-mounted camera can determine the distance of oncoming traffic and relay that information to the BCM, which then continuously adjusts the length of the headlight beam. Some manufacturers add the ability to shade or block light within the beam based on the position of oncoming traffic. Either shields are moved to block light from specific areas or, in the case of LED lights, specific LEDs are switched off to provide the shaded area. In either case, maximum illumination is maintained without blinding oncoming drivers.

Some types of headlights can improve forward lighting while cornering. This type of headlight swivels slightly through the horizontal plane, so that the headlight turns into the corner as the driver turns the steering wheel Figure 39-27. This provides better illumination of the road as the vehicle turns through the corner. In this system, sensors from the steering wheel provide information to a BCM that causes servomotors installed on the headlights to operate, causing the lights to swivel in the desired direction.

BCM Lighting Systems

When driving at dusk, the ambient light can fade slowly. In some vehicles, an ambient light sensor determines when light levels are low. It is read by the BCM, which turns the headlights on, when set on “automatic” Figure 39-28.

Automatic “dimming” headlights use a light sensor located at the front of the vehicle or on the dash to detect light from oncoming vehicles. If the headlights are on, low beam is selected automatically. This prevents oncoming traffic from being dazzled by the vehicle’s high beam. If the light sensor is not signaling that a vehicle is approaching within the defined range, the BCM will select high beams. As a vehicle approaches, the light sensor will signal the BCM, which will select the low beams again. Most vehicles have an adjustable knob that will set the sensitivity of the light sensor. Making it less sensitive will cause the BCM to switch to low beam when the approaching vehicle is closer in range. More sensitivity will cause the BCM to select low beams when the vehicle is farther away.

FIGURE 39-26
Auto-leveling headlights.
FIGURE 39-27
Headlights that shine around a corner.
FIGURE 39-28
Automatic headlight system.

A delayed “off” feature allows the headlights to be left on after the engine has stopped and the doors are closed or locked. This feature allows the driver to safely see his or her way from the vehicle. The headlights automatically turn off after a period of time. On some vehicles, the BCM will turn the headlights off if the headlights are left on after the ignition is off and the driver’s door is left opened. On other vehicles, headlight warning alarms sound if the headlights are left on after the engine has been turned off and a door is opened. This feature reduces the risk of the headlights draining the battery. Many vehicles have an adjuster or can be programmed to tailor the length of this delay time up to a few minutes.

On some vehicles, the BCM, in concert with a lamp-out module, illuminates a warning light in the instrument panel cluster when an exterior light bulb such as a stop, tail, or turn signal light has failed. To detect this malfunction, the lamp-out module compares current flowing through these circuits to values stored in the computer’s memory. If the current flowing is outside the set parameters, the warning light will illuminate. Besides providing the correct amount of light, this is another reason to always use bulbs of the proper wattage.

The BCM can be programmed to command the interior lighting to remain on after the doors have been closed for a set period of time, to allow the occupants to locate a seat belt or insert the ignition key. It can also turn on the interior lighting when the ignition is turned off to allow the occupants to locate door handles and other items.