Pos. | spare part no | Name |
1 | - | Lighting off |
2 | - | Switching on side lights |
3 | - | Headlights on |
4 | - | Switching on the automatic headlight control system (with this feature) |
5 | - | Rotary headlight range adjustment (only halogen headlights) |
6 | - | Rear fog light switch |
7 | - | Rotary light switch |
8 | - | Front fog light switch |
9 | - | Interior lighting rotary control (Dimmer) |
The light switch module is located on the dashboard on the driver's side, with its help the driver selects the appropriate mode of operation of the exterior lighting systems. There are three variants of this module, depending on the vehicle configuration and target market.
The light switch module detects all switching operations and sends messages on the LIN bus to the CJB.
Rotary light switch
The lighting control module is equipped with a central rotary switch that allows you to select the following modes:
- All exterior lights are off
- Side lights included
- Headlights on
- Automatic headlights active
Headlight range adjustment (other countries, only halogen headlights)
NOTE: Headlight range adjustment is not available on North American vehicles with halogen headlights.
The dimmer rotary knob is located on the right side of the light switch module. The rotary knob is connected to a rheostat which sends a variable output signal to the headlight beam leveling stepper motors. The electric motors respond to this output signal and, as necessary, adjust the headlight beams vertically.
This handwheel has no fixed positions, it can be turned to the desired position to compensate for the reduction in the height of the rear of the car, so as not to dazzle other drivers with bright lights.
Light brightness control
The rotary knob for the dimmer is located on the left side of the light switch module. The brightness of the backlight of the instrument panel and other components of the control panel is adjusted using pulse-width modulated signals.
The dimming is done by turning a handwheel which is connected to a rheostat and a switch in the high level circuit. A rheostat is a variable resistance. The rheostat voltage signal is transmitted to the switching capacitor. The high level switch uses the voltage output of the rheostat to set the frequency at which the capacitor turns on, which generates 8-12V pulse-width modulated pulses that determine the light level.
Fog lights
Two switches are provided to select front and rear fog/lights. The front fog lamp switch is only available on vehicles equipped with front fog lamps.
The fog/light switches are momentary switches that, when pressed, generate a message on the LIN bus from the light switch module to the CJB. The fog lights/lights remain active until the selection is deselected with the appropriate fog/light switch or headlights off, or power mode for ignition 6 is changed to power off mode 0.
Automatic headlights
Automatic headlight control is designed to facilitate the work of the driver. The driver can override the system by turning on the headlamps or headlights if there is not enough natural light and activation of the front and rear lights is required.
The automatic headlight control system uses a light sensor and a CJB unit connected to the sensor by a local LIN data bus.
The light sensor, combined with the rain sensor, is located on the inside of the windshield under the rearview mirror. The rain/light sensor signals are also used by the automatic wiper control. For more information, see the chapter: Windshield wipers and washers (501-16 Windshield wipers and washers, Description and principle of operation).
The light sensor measures the level of illumination of the car, both in the vertical direction and the lateral illumination of its front. During operation, the rain / light sensor uses information about the speed of the vehicle, the position of the wiper switch, as well as the position «parking» wiper blades.
The automatic headlight control uses an ambient light signal that is measured by a photodiode built into the rain sensor. The rain/light sensor sends a light on/off request to the CJB via the local LIN bus, which responds to the request by turning on the low beam headlights, front position lights, license plate lights, and rear lights. The automatic headlight control system is activated under the following conditions:
- Twilight
- Night time
- Rain
- Tunnels
- Underground or multi-storey car parks
Automatic headlights require the ignition to be on (power mode 6), the rotary light switch has been set to 'AUTO' and a request to turn on the lights has been received from the light sensor.
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