Function

Function

Bi-Xenon headlights









Lighting the lamp
There is normally a 3 second delay between activation with the light switch or ignition on and the lamp coming on.
- As with normal headlights, the lamps remain off while the starter motor is cranking and come on once the engine is running.
- Each time voltage is supplied to the ballast, 3 one-second attempts are made to light the lamp.

Combined high and low beam

Reflector, left headlight




The illustration is an outline diagram showing the various segments of the moveable reflector.
The reflector has a complex shape in which different segments are used depending on whether high beam or low beam is in use.
The reflector is moveable suspended and is moved between two fixed positions.
- The reflector is moved 2 mm (0.08 in) axially in relationship to the lamp.
- The direction of the movements also causes the reflector to shift slightly vertically.
The lamp remains in a fixed position.
The headlight lens is clear.

Automatic level control

Sensor
The following applies to cars without Four-C (Continuously Controlled Chassis Concept)
An inductive position sensor reads the angle between the body and the left rear control arm. The angle is a indication of how much the vehicle is leaning (chassis height) and depends on weight distribution.
- The sensor is mounted slightly differently for FWD and AWD.
- The rear electronic module (REM) reads off an analog signal (0.5 - 4.5 V) from the position sensor and converts it to an angle value (±35°), which is sent to the central electronic module (CEM).
- A fully loaded vehicle generates a signal of 0.5 V, which corresponds to negative 35°.
- The central electronic module (CEM) regulates the headlight levelling motors (PWM signal) to adjust the headlights vertically.
The following applies to vehicles with Four-C
Two sensors read the angle between the body and the left and right rear control arm. The angle is a indication of how much the vehicle is leaning (chassis height) and depends on weight distribution.
The sensors are mounted slightly differently for FWD and AWD.
The suspension module (SUM) reads off the signals from the sensors and converts them to an angle value. The value is sent to the central electronic module (CEM) via the CAN network. The central electronic module (CEM) uses the information to regulate the headlight levelling motors.

Level control
Regulation at speedsbelow 4 km/h (2.5 mph)
When the ignition is switched on, the position sensor is read and the headlight levelling motors adjust the headlights.
Regulation at speedsabove 4 km/h (2.5 mph)
The headlights are regulated if there are great angle changes while driving. Regulation is time-dependant so that the system does not react to short changes, such as unevenness in the road surface.

Calibration
The position sensor must be calibrated after work on the rear suspension. Perform calibration as described in the tab DIAGNOSTICS/VEHICLE COMMUNICATION, Rear electronic module (REM).

Caution! Calibration must be carried out after work such as removing/installing the sensors and replacing the sensors, rear axle, bushings, shock absorbers or springs.In vehicles with Four C, calibration is carried out via the suspension module (SUM).Beam adjustment is carried out conventionally (via adjustment screws by the headlight).The light switch must be in the "on" position while calibrating.

Safety
- In the event of a short-circuit on the high voltage side, the power supply is cut off for less than 10 ms.
- If the high voltage circuit is broken (such as due to an open circuit, defective bulb or no bulb in the lamp socket), during each activation the system attempts to light the lamp for a period of 700 ms. During the period, there is high voltage across the ballast.
- Approximate component temperatures during operation: Ballast = 130 °C (266 °F), Bulb holder = 170 °C (338 °F), Bulb = 400 °C (752 °F).
- The glass body of the Bi-Xenon lamp is filled with various gases and metal vapors and is under pressure. Because the lamp is subjected to gas pressure, it could explode.

Warning! Follow the safety instructions and recommendations in VIDA carefully when working with high voltage.Use safety goggles when handling the bulb. Risk of explosion!The electrical system must be switched off before starting work.Risk of burn injury. The components operate at very high temperatures.

High voltage unit




- High voltage is required to light the Xenon lamp.
- A high voltage unit is connected to each Xenon lamp. This transforms 12-V voltage to the approximately 24,000 V required to light the lamp. Once the lamp is on, voltage is lowered to the approximately 100 V required to keep the lamp lit.
- Each time voltage is supplied to the high voltage unit, an attempt is made to light the Xenon lamp. If this voltage does not exceed 9.5 V during a time period of 200 ms, the lamp does not light. If voltage is too low, such as after a voltage-consuming cold start, the lamp does not light just because the engine is running and the alternator begins charging. A new attempt must be made to start the lamp by turning the light switch to the "0" or parking light position and then back to the low beam position.

Warning! Because of the high voltage it is important to follow the instructions for working with the Xenon lamps and high voltage unit!