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Headlamp Control Module: Description and Operation

With the ignition SW turned ON, current flows to TERMINAL 1 of the automatic light control sensor through ECU-IG fuse. Voltage is applied at all times to TERMINAL 6 of the automatic light control sensor through the taillight relay (Coil side), and to TERMINAL 5 of the sensor through the HEAD relay (Coil side) (USA) or through the daytime running light relay (Main) (Canada).

AUTOMATIC LIGHT CONTROL
When the light control SW is in AUTO position, if the automatic light control sensor detects a decrease in the ambient light (to between 90 and 475 lux), the automatic light control sensor is activated. About 5.8 seconds after it is activated, current flows from TERMINAL 4 of the sensor to TERMINAL 12 of the light control SW to TERMINAL 16 to GROUND, lighting up the headlights and taillights.

If the ambient light drops below 90 lux, the automatic light control sensor is activated and about 2.9 seconds later, current flows from TERMINAL 4of the sensor to TERMINAL 12 of the light control SW to TERMINAL 16 to GROUND, lighting up the headlights and taillights.

When the light control SW is in AUTO position and activation of the automatic light control sensor has turned ON the headlights and taillights, if the automatic light control sensor detects the ambient light above 1000 lux, the sensor is turned OFF after about 5.8 seconds. So the current from TERMINAL 4 of the sensor to TERMINAL 12 of the light control SW is cut OFF, and the headlights and taillights are turned OFF.


With the ignition SW turned ON, the current flows to TERMINAL 7 of the integration relay through GAUGE fuse. Voltage is applied at all times to the integration relay through the taillight relay (coil side), and to the integration relay through the HEAD relay (coil side) (USA) or through the daytime running light relay (Main) (Canada).

1. NORMAL LIGHTING OPERATION
Turning taillight ON
With the light control SW turned to TAIL position, a signal is input into the integration relay. Accordingly, the current flows to the integration relay to TERMINAL 14 of the light control SW to TERMINAL 16 to GROUND, and taillight relay causes taillights to turn ON.

Turning headlight ON
With the light control SW turned to HEAD position, a signal is input into the integration relay. Accordingly, the current flows to the integration relay to TERMINAL 13 of the light control SW to TERMINAL 16 to GROUND in the headlight circuit, and the taillight relay and HEAD relay turn the lights ON. The taillight circuit operation is same as above.

2. LIGHT AUTO TURN OFF OPERATION
With the lights ON and the ignition SW turned OFF (Input signal goes to TERMINAL 7 of the integration relay), when the driver's door is opened (Input signal goes to TERMINAL 6 of the integration relay), the relay operates and the current which flows to the integration relay in the taillight circuit and the integration relay in the headlight circuit is cut OFF.

As a result, all lights are turned OFF automatically.