Headlamp: Description and Operation

Current from the Battery is always flowing from the FL Main --> MAIN NO.1 Head Relay (Coil side) --> TERMINAL 5 of the Daytime Running Light Relay (Main) and TERMINAL 14 of the Dimmer SW [Comb. SW], Head Relay (Coil side) --> TERMINAL 3 of the Integration Relay --> TERMINAL 4 --> TERMINAL 13 of the Light Control SW [Comb. SW], FL Main --> MAIN NO.1 Fuse --> Dimmer Relay (Coil side) --> TERMINAL 17 of the daytime running Light Relay, (Main).

1. DAYTIME RUNNING LIGHT OPERATION
When the engine is started, voltage generated at TERMINAL 'L' of the Generator is applied to TERMINAL 11 of the Daytime running Light Relay (Main).

If the Parking Brake Lever is pulled up (Parking Brake SW ON) at this time, the Relay is not energized, so the daytime running light system does not operate. If the Parking Brake lever is released (Parking Brake Lever SW OFF), the signal is input to TERMINAL 8 of the Relay. This activates the Relay and current from MAIN NO.1 flows to Dimmer Relay (point side) --> HEAD HI (LH) fuse --> TERMINAL 1 of the Headlight HI LH --> TERMINAL 2 --> TERMINAL 2 of the Headlight HI-RH --> TERMINAL 1 --> TERMINAL 4 of the DRL No.3 Relay --> TERMINAL 2 to GROUND, causing the headlights to light up dimmer than normal brightness.

This is how the Daytime running Light System operates once the Daytime Running Light System operates and Headlights have light up, the headlights remain ON even if the Parking Brake Lever is pulled up (Parking Brake SW ON).

Even if the engine stalls with the Ignition SW ON and there is no voltage from TERMINAL 'L' of the Generator, the Headlights remain ON. If the Ignition SW is then turned OFF Headlights are turned OFF.

If the engine is started while the Parking Brake Lever is released (Parking Brake SW OFF), the Daytime Running Light System operates and Tail, Head Light up as the engine starts.

2. HEADLIGHT OPERATION
* When the Light Control SW [Comb. SW] at the HEAD Position
When the Light Control SW [Comb. SW] is set to HEAD position, the current flowing to the Head Relay (coil side) flows to TERMINAL 3 of the Integration Relay --> TERMINAL 4 --> TERMINAL 13 of the Light Control SW [Comb. SW] --> TERMINAL 11 --> GROUND, turning the Headlight Relay ON.

This causes the current flowing to the Head Relay (point side) --> DRL Fuse DRL No.3 (coil side) and DRL No.4 (coil side) --> GROUND, turning the DRL No.3 and No.4 Relay ON. Also, current from the Head Relay (point side) to HEAD (LWR) fuses --> TERMINAL 1 of the Headlights (LO) --> TERMINAL 2 --> GROUND, so the Headlights (LO side) light up.

* Dimmer SW [Comb. SW] at FLASH position
When the Dimmer SW is set to FLASH position, current flows from Head Relay (coil side) --> TERMINAL 14 of the Dimmer SW [Comb. SW] --> TERMINAL 9 --> GROUND, turning the Head Relay ON. At the same time, signals are output from TERMINAL 12 and TERMINAL 14 of the dimmer SW [Comb. SW] to TERMINAL 16 and TERMINAL 5 of the Daytime Running Light Relay (Main), activating the Daytime Running Light Relay (Main) and also the Dimmer Relay No.2. When the Head Relay and Daytime Running Light Relay (Main) are activated, the Headlights (LO and HI) then light up.

* Dimmer SW [Comb. SW] at HIGH position
When the Light Control SW [Comb. SW] is set to HEAD position, a signal is output from TERMINAL 13 of the Light Control SW [Comb SW] -->TERMINAL 4 of the Integration Relay --> TERMINAL 3 --> TERMINAL 5 of the Daytime Running Light Relay (Main). When the Dimmer SW [Comb. SW] is set to HIGH position, a signal is output from TERMINAL 12 of the dimmer SW [Comb. SW] to TERMINAL 16 of the Daytime Running Light Relay (Main). These signals activate Dimmer Relay, so current flows from Dimmer Relay (point side) --> HEAD (HI-LH) Fuse --> TERMINAL 1 of the Headlight HI-LH --> TERMINAL 2 --> DRL NO.4 Relay (Point side) --> GROUND and current also simultaneously flows from HEAD HI (RH) Fuse --> DRL No.3 (point side) --> TERMINAL 1 of the Headlight HI RH --> TERMINAL 2 --> DRL No.4 Relay (point side), causing the headlights (HI side) to light up.