Ambient Light Sensor: Description and Operation
SYSTEM OUTLINEWhen the light control SW is set at AUTO, the automatic light control system automatically turns on or oft the taillights and headlights depending on the brightness around the vehicle.
AUTOMATIC LIGHT CONTROL OPERATION
The automatic light control sensor converts the intensity of the illumination into frequency and inputs it to the body ECU No.2. When the light control SW is set at AUTO, the signal is input to TERMINAL AUTO of the body ECU No.2. Through communication control of the body ECU and door ECU etc., the taillights and headlights are automatically turned on or off.
Turn on operation
When the body ECU No.2 receives the frequency signal from the automatic light control sensor and determines that the brightness around the vehicle has decreased below a specified level, TERMINAL TRLY and HRLY of the body ECU No.2 are controlled through communication control of the body ECU and door ECU etc. As a result, the taillights and headlights light up as the TAIL relay and HEAD LP relay are turned on.
Turn off operation
When the body ECU No.2 receives the frequency signal from the automatic light control sensor and determines that the brightness around the vehicle has exceeded a specified level, TERMINAL TRLY and HRLY of the body ECU No.2 are controlled through communication control of the body ECU and door ECU etc. As a result, the taillights and headlights go oft as the TAIL relay and HEAD LP relay are turned off.
Additionally, when the ignition SW is changed from ON to OFF and any door is opened, and then closed with the taillights and headlights lit (The automatic light control is functioning), the taillights and headlights are turned oft in the same manner as the light auto turn oft operation.