Lighting and Horns: Description and Operation

LIGHTING: LIGHTING SYSTEM: SYSTEM DESCRIPTION

SYSTEM DESCRIPTION

The system representations shown below are intended to show concept of operation, and may not precisely reflect the construction of the system on the vehicle.
1. AUTOMATIC LIGHT CONTROL SYSTEM
(a) General
(1) When the light control switch is in the AUTO position, the automatic light control system detects ambient light levels and controls the headlights, parking lights, taillights, marker lights, and license plate lights.

- The main body ECU RH controls this system.
- The headlight dimmer switch includes the tilt and telescopic switch, fog switch, turn switch, dimmer switch, and light control switch. The headlight dimmer switch signals are received by the windshield wiper switch assembly, and the windshield wiper switch assembly forwards these signals to the main body ECU RH using the Body Electronics Area Network (BEAN).
- A direct headlight backup link (HEAD) exists between the windshield wiper switch assembly and the main body ECU RH. If this link is grounded, the headlights will illuminate.
- Ambient light levels are detected by the light control sensor that is integrated in the air conditioning system's solar sensor. This signal is received directly by the main body ECU RH (cowl side junction block RH).
- The dimmer circuit in the combination meter controls the ground for the panel illumination.
- The combination meter bases the control of the panel illumination on signals received from the light control rheostat, and other inputs.
- The main body ECU RH controls the taillights and panel illumination using the tail relay that is built into the main body ECU LH (cowl side junction block LH).
- The main body ECU RH controls the low beam illumination using the HEAD LP relay.





- The front controller uses transistors to directly operate the high beams for models that have DRL. For models without DRL, the front controller operates the high beams using a HEAD HI relay that is built into the front controller.
- The front controller operates the front parking lights and front marker lights using the FR TAIL relay that is built into the front controller (engine room No. 2 relay block).
- The front controller operates the front fog lights using the FR FOG relay that is built into the front controller (engine room No. 2 relay block).





2. MANUAL LIGHT CONTROL SYSTEM
(a) The function of the system is similar to the automatic light control system, except the system is controlled according to the driver's inputs.
3. BI-FUNCTION
(a) The models with HID (High Intensity Discharge) headlights have a Bi-function. This Bi-function increases the upper illumination area of the discharge bulb (LO/HI beam) when the HI beam is turned on.
- If the LO beam is selected, the upper illumination area of the discharge bulb is blocked by a shade and only the lower illumination area is used. If the HI beam is selected, the headlight solenoid slides the shutter (shade) down to allow use of the upper illumination area, thus increasing the illumination area and improving visibility when the HI beam is on.
- This function is activated by the front controller. The front controller receives a HI beam turn ON signal from the main body ECU RH and activates the headlight solenoid built into the headlight unit to slide the shade down.





4. HID HEADLIGHT SYSTEM
(a) This system consists primarily of the light control switch, windshield wiper SW assembly, main body ECU RH, HEAD LP relay, discharge bulbs, and light control ECUs.
- The main body ECU RH controls the low beam illumination using the HEAD LP relay.
- The BEAN network is used for communications.
- A HEAD backup link exists between the windshield wiper switch and the main body ECU RH.
- The light control ECUs transform the voltage that is input from the battery to a high voltage of up to 20,000 V and apply this voltage to the discharge bulbs in order to illuminate them.
- A fail-safe function is provided as a countermeasure against the high voltage that is generated in case that a problem occurs in the headlight system.




NOTE:
For safety reasons, do not attempt to measure the voltage output from a light control ECU.

5. AUTOMATIC HEADLIGHT BEAM LEVEL CONTROL SYSTEM
(a) When the headlights are on, the automatic headlight beam level control system operates the headlight level actuators in accordance with the movement of the vehicle.
- The automatic headlight beam level control system mainly consists of the AFS ECU, front height control sensor, rear height control sensor, and two headlight level actuators. The AFS ECU controls the system.
- The ECU detects the movement of the suspension from the front and rear height control sensors, and the vehicle speed from the front RH and LH speed sensors.
- The ECU then controls the headlight level actuator based on this information, in order to change the headlight reflector angle.
- The AFS ECU controls both the level control system and the intelligent AFS system.

(b) Initial Set Control
- the AFS ECU executes the initial setting of the stepper motors at engine-start.

(c) Fail-Safe Function
- If the AFS ECU detects a malfunction in the automatic headlight beam level control system, the AFS ECU effects fail-safe control. At the same time, the AFS ECU flashes the AFS OFF indicator light in order to inform the driver of the problem.

6. INTELLIGENT AFS (ADAPTIVE FRONT-LIGHTING SYSTEM)
(a) An intelligent AFS (Adaptive Front-lighting System) is used in order to turn the LO/HI (discharge) beam toward the inside of the cornering direction.
(b) The separate (incandescent) HI beam illumination is not controlled by this system.

Swivel Angle Range





- This system consists of the two headlight units for LO/HI beam (discharge illumination), the AFS ECU, two headlight swivel actuators, steering angle sensor and front speed sensors. The AFS ECU controls this system.
- The AFS ECU also controls the automatic headlight beam level control system.
- The system does not control the incandescent HI beam illumination.
- The lights controlled by this system (LO/HI beam) are shown in the Front Lighting illustration.

(c) The AFS ECU performs intelligent AFS control when all the following conditions are fulfilled.
- Engine is running.
- Vehicle is moving* forward at 6 mph (10 km/h) or more, or stopped.
- Steering angle* is 7.5° or more.
- Headlight LO/HI beam operates.
- Daytime running light system is not operating.
- AFS ON/ OFF condition is ON.
*: Swivel angle change is in accordance with the vehicle speed and steering angle.

- The minimum vehicle speed to change the swivel is 6 mph (10 km/h) if the steering angle is wide.
- The minimum steering angle to change the swivel is 7.5° if the vehicle speed is high.

(d) The AFS ECU calculates the target lighting angle of the LO/HI beam based on the steering angle and the vehicle speed. Then, it actuates the headlight swivel actuators in order to attain the target lighting angle.
(e) The operation angle of the headlights is detected by the position (number of steps) of the stepper motor in the headlight swivel actuator.
7. DAYTIME RUNNING LIGHT SYSTEM
(a) The daytime running light system is designed to automatically illuminate the headlights (dimmed HI beams), during the daytime to make the car more visible to other vehicles.
- The main body ECU RH and front controller control this system. The main body ECU RH transmits a turn ON signal to the front controller, and the front controller illuminates the HI beams using a duty control.
- This system is enabled when the conditions given below are met:

- Power source: IG-ON
- Engine speed signal input (engine running condition)
- Light control switch OFF, TAIL, or AUTO position (if headlight-on control is not being performed by the automatic light control)
- Parking brake switch: OFF
HINT:
The lights that are controlled are shown in the Front Lighting and Rear Lighting illustrations.

8. ILLUMINATED ENTRY SYSTEM
(a) General
(1) The illuminated entry system has the seven control functions shown in the following chart:










*1: Illuminates for approximately 15 seconds, fades out (fades out over three seconds).
*2: Stops the illumination, starts to fade out immediately (fades out over three seconds).
*3: The footwell lights go off when the light control rheostat is adjusted to the minimum level.
9. TURN SIGNALS
(a) The turn signals are front, rear and side lights that can be used to indicate a change of vehicle direction.
- The turn signal switch signals are received by the windshield wiper switch assembly (combination switch ECU).
- The main body ECU LH operates the turn signal flasher.
- The turn signal flasher operates the signal lights.
HINT:
The lights that are controlled are shown in the Front Lighting and Rear Lighting illustrations.

10. HEADLIGHT CLEANER SYSTEM
(a) Some vehicles are provided with a headlight cleaner system. More details on the headlight cleaner system operation can be found in the wiper section.

SYSTEM DIAGRAM

























Various switches or sensors are represented as inputs for the different systems mentioned in the section. Where direct electrical connections do not exist between components, signals may be carried across the different networks (BEAN, CAN) that exist on the vehicle. If a signal needs to travel from the CAN network to the BEAN network, the gateway ECU allows the signal to travel between these different networks. Some of these different signals can be confirmed or inspected using the Techstream.