Headlamp Control Module: Description and Operation

With the ignition SW turned ON, current flows to TERMINAL 1 of the light retainer relay through the ECU-IG fuse. Voltage is applied at all times to TERMINAL 8 of the light retainer relay through the tail relay (coil side), and to TERMINAL 7 of the light retainer relay through the head relay (coil side).

1. NORMAL LIGHTING OPERATION
With the light control SW turned to TAIL position, a signal is input into TERMINAL 2 of the light retainer relay. Due to this signal, the current flow to TERMINAL 8 of the relay flows through TERMINAL 2 to TERMINAL 2 of the light control SW --> TERMINAL 11 --> GROUND, causing taillights to turn ON.

With the light control SW turned to HEAD position, a signal is input into TERMINAL 3 of the light retainer relay. Due to this signal, the current flow to TERMINAL 7 of the relay flows through TERMINAL 3 to TERMINAL 13 of the light control SW --> TERMINAL 11 --> GROUND, causing headlights and taillights to turn ON. The taillight circuit is same as above (see
2. LIGHT AUTO TURN OFF OPERATION
With lights ON and the ignition SW turned OFF (input signal goes to TERMINAL 1 of the light retainer relay), when the driver's door is opened (input signal goes to TERMINAL 5 of the light retainer relay), the relay operates, and the current is cut off which flows from TERMINAL 8 of the relay to TERMINAL 2 and from TERMINAL 7 of the relay to TERMINAL 3. As a result, all lights are turned OFF automatically.