Daytime Running Lamp: Description and Operation

System Outline

The current is always flowing from the ECU B2 fuse to TERMINAL 7 of the daytime running light relay (Main). When the ignition SW is turned on, the current flowing through the ECU IG fuse flow to TERMINAL 1 of the daytime running light relay (Main).

1. DAYTIME RUNNING LIGHT OPERATION

When the engine is started, the generator signal is input from the combination meter to TERMINAL 5 of the daytime running light relay (Main). At this time, when the parking brake lever is pulled up (The parking brake SW is on), the relay is not activated and the daytime running light system does not function. When the parking brake lever is released (The parking brake SW is off), the signal is input to TERMINAL 4 of the daytime running light relay (Main). This activates the relay to turn on the DIMMER relay. The current flows from the battery into the MAIN fuse to DRL NO.2 fuse to DIMMER relay (Point side) to H LP L UPR fuse to TERMINAL 2 of the headlight LH (High) to TERMINAL 1 to TERMINAL 1 of the headlight RH (High) to TERMINAL 2 to TERMINAL (A) 5 of the daytime running light relay No.3 to TERMINAL (A) 3 to TERMINAL 1 of the daytime running light resistor to TERMINAL 2 to GROUND. The headlights light up more dimly than usual as the engine is started.

Once the daytime running light system has been activated, the headlights are remained lit even though the parking brake lever is pulled up (The parking brake SW is on). Even if the engine is stopped and the generator signal is cut off with the ignition SW set at ON, the headlights are remained lit. When the ignition SW is turned from ON to OFF, the daytime running light system is stopped and the headlights go off. If the engine is started with the parking brake lever is released, the daytime running light system starts functioning and the headlights light up as the engine is started.

2. HEADLIGHT OPERATION

- Light control SW is set at HEAD.
When the light control SW is set to HEAD position, the signal is input to TERMINAL 12 of the theft deterrent ECU. This activates the theft deterrent ECU and turns on the HEAD LP relay. When the signal is input to TERMINAL 2 of the daytime running light relay (Main), the daytime running light system is deactivated and headlights LH and RH (High) go off. At this time, the current flows from the battery into the MAIN fuse to HEAD LP relay (Point side) to H-LP L LWR and H-LP R LWR fuse to TERMINAL 2 of the headlight control ECU LH and RH to TERMINAL 1 to GROUND, to turn on the headlights (Low beam).

- Dimmer SW is set at HIGH.
When the light control SW is set to HEAD position, the current flows from DRL No.1 fuse into the daytime running light relay No.3 and No.4 (Coil side) to turn on the relay as the headlights (Low beam) light up. At this time, when the dimmer SW is set to HIGH position, the signal is input to TERMINAL 8 of the daytime running light relay (Main). This activates the DIMMER relay to flow the current from the battery into the MAIN fuse to DRL NO.2 fuse to DIMMER relay (Point side) to H-LP L UPR fuse to headlight LH (High) to daytime running light relay No.4 (Point side) to GROUND and the current flows from H-LP R UPR to daytime running light relay No.3 (Point side) to headlight RH (High) to daytime running light relay No.4 (Point side) to GROUND, to turn on the headlights (High and low) and high beam indicator light at the same time.

- Dimmer SW is set at FLASH.
When the dimmer SW is set to FLASH position, the current flows from the battery into the MAIN fuse, HEAD LP relay (Coil side) to TERMINAL 8 of the combination SW to TERMINAL 16 to GROUND in that order to turn on the HEAD LP relay.
Additionally, the signal is input to TERMINAL 8 of the daytime running light relay (Main) to activate the relay and turn on the DIMMER relay. In the same manner as the dimmer SW set at HIGH position, the headlights (High and low) and high beam indicator light are turned on at the same time.