Function

Function

Headlamps, Bi-Xenon










Lighting the headlamp
It normally takes 3 seconds from activation at the light switch with the ignition on to the lamp lighting.
- Like conventional headlamps the headlamps are out while the engine is cranking and do not light until the engine is running
- On each occasion that voltage is supplied to the ballast 3 attempts, within 1 second, are made to light the lamp.

Combined high and low beam

Reflector, left-hand headlamp




The illustration is a principle sketch showing the different segments of the moving reflector.
The reflector has a complex design where different segments are used depending on whether in high or low beam position.
The reflector is adjustable and can be moved between two fixed points.
- The reflector is moved 2 mm axially in relation to the bulb
- The direction of the movement means that position of reflector is also moved slightly vertically.
The bulb is fixed.
The headlamp lens is clear.

Automatic level control

Sensor
The following applies to vehicles without Four-C (Continuously Controlled Chassis Concept)
An inductive position sensor reads off the angle between the bodywork and the left rear control arm. The angle is a measurement of how much the vehicle is leaning (chassis height) and is dependent on weight distribution.
- The sensor is mounted differently in FWD to AWD
- The rear electronic module (REM) reads an analog signal (0.5-4.5 V) from the position sensor and converts it to an angle value (±35°), which is transmitted to the central electronic module (CEM)
- Fully laden vehicles give a signal of 0.5 V which corresponds to minus 35°.
- The central electronic module (CEM) controls the motors for the headlamp range adjustment (PWM signal) and sets the headlamps vertically.
The following applies to vehicles with Four-C
Two sensors read off the angle between the bodywork and the left and right rear control arms. The angle is a measurement of how much the vehicle is leaning (chassis height) and is dependent on weight distribution.
The sensors are mounted differently in FWD to AWD.
The suspension module (SUM) reads the signals from the sensors and converts them to an angle value. The value is transmitted via the control area network (CAN) to the central electronic module (CEM). The central electronic module (CEM) uses this information to control the motors for headlamp range adjustment.

Level control
Controlled at speedsbelow 4 km/h
When the ignition is switched on, the position sensor is read off and the headlamp range adjustment motors set the headlamps.
Controlled at speedsabove 4 km/h
At greater angle changes during driving the headlamps are controlled. Control is dependent on the time for the system not to react to short term changes such as uneven road surfaces etc.

Calibration
The position sensor must be calibrated after work on the rear suspension. Carry out calibration according to 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 headlamp). The light switch must be in the "on" position while calibrating.

Safety
- In the event of a short-circuit on the high tension side the power supply cuts in less than 10 ms
- If the high tension circuit is broken (for example by a broken cable, blown bulb or no bulb in the bulb connector) the system attempts to activate the lamp for a time of 700 ms. During this time the high voltage is outside the ballast
- Approximate temperatures on the components during operation are; Ballast = 130 °C, Bulb holder = 170 °C, Bulb = 400 °C
- The glass body of the Bi-Xenon-lamp is filled with different gases and metal vapors which are under pressure. The lamp can explode as it is under gas pressure.

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 attached to each Xenon lamp. It transforms 12 V voltage to approximately 24 000 V, which is necessary to light the lamp. When the lamp is lit the voltage is reduced to the 100 V required to keep the lamp lit
- On each occasion that 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 within a time span of 200 ms the lamp does not light. If the voltage is too low, after a power consuming start for cold start, the lamp does not light until the engine is running and the generator starts to charge. A new start attempt of the lamp must be made by turning the knob of the light switch till "0" position or parking lamp position and then back to low beam again.

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