AUTO LIGHT SYSTEM
id091800010500
Outline
• The auto light system automatically turns the TNS and headlights on/off according to the illumination level above and in front of the vehicle.
• The auto light system is controlled by the BCM.
Function
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Note
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― The following illumination level is a reference. It varies depending on conditions in the surrounding area (weather, reflection off buildings).
― The illumination level sensitivity of the auto light sensor can be changed. The illumination level shown below is the standard set value. For the other settings, refer to
LIGHTING SYSTEM PERSONALIZATION.
• The auto light system receives a headlight illumination/off request signal from the auto light sensor and the BCM turns the headlights on and off.
• If the upward and forward illumination sensors detect the illumination level at which the headlights should be illuminated/turned off, the auto light sensor sends a headlight illumination/off request signal.
• If the auto light sensor detects that the vehicle is being driven at night after sending the headlight illumination request signal, it switches to the night mode and changes the headlight off conditions so that the headlights do not turn off and on repeatedly due to temporary brightness from street lights or store lighting, making it difficult for the headlights to turn off.
Night mode
• When the upward and forward illumination level sensors detect an illumination level of approx. 2,000 lux or less for approx. 10 min after sending the headlight illumination request signal, the auto light sensor determines that the vehicle is being driven at night and the auto light system is switched to the night mode.
• The auto light sensor determines the headlight off condition based on the average illumination level for the previous 3 min detected by the upward and forward illumination level sensors while in the night mode.
• If the average illumination level of the calculated past 3 min is approx. 4,000 lux or more, the auto light sensor cancels the night mode and sends a headlight off request signal.
• When a headlight switch OFF signal is input while in the night mode, the auto light sensor cancels the night mode.
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Caution
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• If the vehicle is driven a long-distance in a tunnel, the traffic is congested inside a tunnel, or the environment (temperature, buildings, tree shadows) surrounding the vehicle is dark for approx. 10 min, even if the surroundings are bright during daytime, the conditions for driving at night will be met and the auto light sensor may switch to the night mode.
• Because turning off of the headlights is determined by the average illumination level for the past 3 min when the mode is switched to the night mode during daytime while the surrounding area is bright, if the vehicle is driven in an environment (temperature, buildings, or tree shadows) surrounding the vehicle which is dark, the average illumination level may be insufficient and the condition for turning off the headlights may not be met, therefore the night mode may not cancel (headlights continue to illuminate).
Structural View
System Wiring Diagram
Operation
• The auto light system functions when the ignition is switched ON and the light switch is in the AUTO position.
Illumination operation
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Note
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― The following illumination level is a reference. It varies depending on conditions in the surrounding area (weather, reflection off buildings).
― The illumination level sensitivity of the auto light sensor can be changed. The illumination level shown below is the standard set value. For the other settings, refer to
LIGHTING SYSTEM PERSONALIZATION.
1. When the ignition is switched ON and the light switch is turned to the AUTO position, the auto light sensor installed to the windshield glass detects the illumination level above and in front of the vehicle.
2. If the illumination level sensor detects approx. 2,000 lux or less for approx. 0.25 to 2.25 s, a TNS and headlight (LO) on control signal is sent to the BCM.
3. When the BCM sends a TNS illumination signal and headlight (LO) illumination signal, base current flows to transistor and it turns on.
4. When transistor turns on, the TNS relay and headlight relay (LO) turns on, and the TNS and headlights (LO) illuminate.
Lights off operation
1. When the ignition is switched ON and the light switch is turned to the AUTO position, the auto light sensor installed to the windshield glass detects the illumination level above and in front of the vehicle.
2. If the auto light sensor detects an illumination level of approx. 4,000 lux or more during an approx. 1.25 to 4.25 period, the auto light sensor microcomputer sends a headlight (LO) and TNS illumination-off signal to the BCM.
3. When the BCM receives the headlight (LO) and TNS illumination-off signal, base current to transistor is stopped and it turns off.
4. When transistor turns off, the headlight relay (LO) and TNS relay turns off, and the headlights (LO) and TNS turn off.
