Exterior Lighting System
LIGHTING (EXT): LIGHTING SYSTEM: SYSTEM DIAGRAM
1. AUTOMATIC LIGHT CONTROL SYSTEM
2. LIGHT AUTO TURN-OFF SYSTEM
Communication Table
3. DAYTIME RUNNING LIGHT SYSTEM
Communication Table
4. AUTOMATIC HIGH BEAM SYSTEM
Communication Table
5. HID HEADLIGHT SYSTEM
6. AUTOMATIC HEADLIGHT BEAM LEVEL CONTROL SYSTEM
SYSTEM DESCRIPTION
1. AUTOMATIC LIGHT CONTROL SYSTEM
When the light control switch is in the AUTO position, the automatic light control system detects ambient light levels and controls the low beam headlights, parking lights, taillights, marker lights and license plate lights.
2. LIGHT AUTO TURN-OFF SYSTEM
The light auto turn-off system is used to prevent the exterior lights from being accidentally left on (low beam headlights, high beam headlights, front fog lights, taillights, parking lights, license plate lights and marker lights).
This system has the following functions.
3. DAYTIME RUNNING LIGHT SYSTEM
The daytime running light system is designed to automatically illuminate the dimmed high beam headlights, during the daytime to make the vehicle more visible to other vehicles.
This system is controlled by the main body ECU (driver side junction block assembly) and power distributor (engine room junction block assembly). The main body ECU (driver side junction block assembly) transmits a turn ON signal to the power distributor (engine room junction block assembly), which illuminates the high beam headlights using duty control.
This system is enabled when the following conditions are met:
* Ignition switch ON
* Engine speed signal input (engine running)
* Parking brake switch off
* Light control switch not in the DRL OFF position (w/ DRL OFF switch)
* Light control switch is in the off (w/o DRL OFF switch), tail or AUTO position (and the low beam headlights are not turned on via the automatic light control system).
4. AUTOMATIC HIGH BEAM SYSTEM
(a) General
The automatic high beam system enhances the illumination of the area to the front of the vehicle to improve visibility for the driver. It works by detecting light from the front using the camera built into the inner rear view mirror assembly and turning the high beams of the headlights on or off automatically.
(b) Function of Main Components
(c) Basic Function
(1) When all of the following conditions are met, the automatic high beam system is activated and the automatic high beam indicator light turns on:
The ignition switch is ON.
The light control switch is in the AUTO position and the low beam headlights are on.
The dimmer switch is in the high position.
(2) When the following conditions are met, the high beams automatically turn on after a short delay:
Vehicle speed is more than approximately 20 mph (32 km/h).
The area in front of the vehicle is dark.
There are no oncoming vehicles with headlights on.
There are no preceding vehicles with taillights on.
There are few street lights along the street ahead.
(3) When any of the following conditions are met, the high beams automatically turn off after a short delay:
Vehicle speed is less than 20 mph (32 km/h).
The level of ambient light is higher than a specified threshold.
There are oncoming vehicles with headlights on.
There are preceding vehicles with taillights on.
There are several street lights along the street ahead.
(4) When any of the following conditions are met, the automatic high beam system will be canceled and the indicator light will turn off.
The ignition switch is turned off.
The light control switch is turned to any position except the AUTO position.
The light control switch is in the AUTO position, however the low beams are not on.
The dimmer switch is moved to the low position.
HINT
It is possible to manually switch between the high beams and low beams using either of the following operations:
* Turn the light control switch from the auto position to the head position. In this case, the high beams turn on according to the dimmer switch high position. To change to the low beams, move the dimmer switch to the low position.
* Move the dimmer switch from the high position to the low position. In this case, the low beams turn on according to the dimmer switch position.
HINT
The automatic high beam system monitors the area in front of the vehicle using the camera built into the inner rear view mirror assembly and makes a judgment to turn on the high beams when the surrounding area is dark (there are no headlights from oncoming vehicles and no taillights from vehicles in front). High beam control limitations:
* When the surrounding area is not dark enough, the low beams will remain on even if the headlights are turned on by the automatic light control system and the automatic high beam indicator light on the combination meter assembly illuminates. (The light level sufficient to turn the auto low beams on is not the same as the light level required to automatically illuminate the high beams.)
* When an oncoming vehicle suddenly appears at a sharp curve or a vehicle crosses the path of the vehicle, the high beams may remain on.
* When the fog lights of an oncoming vehicle are detected, the high beams may be turned off.
* The timing of the high beams turning on and off may differ depending on the brightness of headlights or fog lights from oncoming vehicles or the taillights of preceding vehicles.
* The timing of the high beams turning on and off may differ between normal conditions (good weather) and when driving on wet, frozen or snowy roads.
* The timing of the high beams turning on and off may differ depending on the number of occupants and amount of cargo present.
* On some occasions, the high beams and low beams may change unexpectedly.
HINT
The camera built into the inner rear view mirror assembly continually monitors the light level in the area to the front of the vehicle. There is a delay in turning on the high beams. Even when there is no ambient light, the high beams will not turn on immediately. The delay will vary depend on the situation.
5. HID HEADLIGHT SYSTEM
The High Intensity Discharge (HID) headlight system uses a discharge bulb as its light source for the low beam. Discharge bulbs are superior to halogen bulbs.
Discharge bulbs have the following features:
* The light emitted by the bulb is close in color to sunlight. The light shines further forward and over a broader area, increasing the area visible to the driver.
* Less power is consumed.
This system consists of the discharge bulbs and light control ECUs.
The light control ECU transforms voltage that is input from the battery to high voltage of up to 22000 V and applies it to the discharge bulbs in order to illuminate them.
6. AUTOMATIC HEADLIGHT BEAM LEVEL CONTROL SYSTEM
(a) General
This system maintains the low beam headlights at a constant level while the vehicle is stopping.
This system is controlled by the headlight leveling ECU assembly. The headlight leveling ECU assembly detects the vehicle posture via the rear height control sensor sub-assembly RH, and detects the vehicle speed via the combination meter assembly. The headlight leveling ECU assembly controls each headlight leveling motor (headlight unit) based on these pieces of information in order to change the headlight reflector angle.
NOTICE:
* Initialize the rear height control sensor sub-assembly RH signal after the vehicle height changes due to replacement of the suspension or after operations as reinstallation or replacement of the rear height control sensor sub-assembly RH.
* When the headlight leveling ECU assembly is replaced, initialization is also necessary.
(b) Function of Main Components
