Ambient Light Sensor: Description and Operation

SYSTEM OUTLINE

AUTOMATIC LIGHT CONTROL

When the light control SW is set at AUTO position, this system automatically turns ON/OFF the taillights and headlights depending on the brightness around the vehicle.

AUTOMATIC LIGHT CONTROL OPERATION

1. Turn on operation
- With the ignition SW turned on, and the light control SW set at AUTO position, when the brightness around the vehicle drops in between a predetermined level, the timer of the automatic light control sensor starts counting, and turns on the taillight and headlight after approx. 5.8 seconds have elapsed. In case the brightness around the vehicle increases over a predetermined level during timer counting, the timer will be reset.
- With the ignition SW turned on and the light control SW set at AUTO position, when the brightness around the vehicle drops below a predetermined level, the timer of the automatic light control sensor starts counting, and turns on the taillight and headlight after approx. 2.9 seconds have elapsed. In case the brightness around the vehicle increases in between a predetermined level during timer counting, the timer will be stopped, and when the brightness increases over a predetermined level, the timer will be reset.

2. Turn off operation
- When the brightness increases over a predetermined level while the automatic light control system is operating, the timer of the automatic light control sensor starts counting, and turns off the taillight and headlight after approx. 5.8 seconds have elapsed. In case the brightness around the vehicle drops below a predetermined level during timer counting, the timer will be reset.
- The taillights and headlights will be turned off when the ignition SW is turned from on to off and driver door is opened, during automatic light control system operation, with the light control SW set at AUTO position.

LIGHT AUTO TURN OFF

This system automatically turns off the taillight or headlight by the opening/closing of the driver door, to prevent the lights from remaining lit.

LIGHT AUTO TURN OFF OPERATION

- When headlights are on
When the ignition SW turned from on to off with the headlights on (Light control SW at HEAD position), a signal is input to instrument ECU TERMINAL SIG. When the driver door is opened at this time, a signal is input from the door courtesy SW front LH to the instrument ECU TERMINAL DCY. The instrument ECU TERMINAL HRY is controlled to turn off the HEAD relay. As a result, the current to the headlight is cut off and the light is turned off.

- When taillights are on
When the ignition SW turned from on to off with the taillights on (Light control SW at TAIL position), a signal is input to instrument ECU TERMINAL SIG. When the driver door is opened at this time, a signal is input from the door courtesy SW front LH to the instrument ECU TERMINAL DCY. The instrument ECU TERMINAL TRY is controlled to turn off the TAIL relay. As a result, the current to the taillight is cut off and the light is turned off.