3 Series E91 325i (N52K) TOUR
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E90, E91, E92, E93, E70: [System overview ...]
Note: Only the main beam of the bi-xenon headlights are switched on.
If a main-beam assistant is fitted, only the main beam of the bi-xenon headlights are switched on.
The halogen headlights are switched on only when the headlight flasher is actuated. In countries in which
daytime driving lights are required by law, the halogen headlights are used for the daytime driving lights.
Brief description of components
The following components and control units provide input signals for the main-beam assistant:
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Light switch
The main-beam assistant can be activated only when the light switch is in position "A".
"A" stands for "automatic headlight control".
[for further information, please refer to SI Technology (SBT) 63 02 03 007]
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Turn-signal/main-beam switch
The main-beam assistant is activated and deactivated by mans of the turn-signal/main-beam switch.
See the section entitled "Operation" below.
[for further information, please refer to SI Technology (SBT) 63 02 03 007]
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Rain-light sensor
The rain-light sensor measures the brightness of the ambient light. The light module switches the dipped
headlights on when daylight fails.
The main-beam assistant can be activated only when the dipped headlights are on. The precondition is that the
light switch must be in the "A" position.
[for further information, please refer to SI Technology (SBT) 63 02 03 007]
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Wheel-speed sensors
Each of the wheel-speed sensors measures the circumferential speed of an individual wheel. The DSC control
unit (DSC: Dynamic Stability Control) uses these input signals to calculate the car's road speed.
The main-beam headlights are switched on when the car's road speed is above 50 km/h.
The main-beam headlights are switched off when the car's road speed is below 38 km/h.
[for further information, please refer to SI Technology (SBT) 34 01 05 126]
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DSC sensor
The DSC sensor registers lateral acceleration and calculates the yaw rate.
("Yaw" is the movement of the vehicle about the vertical axis, e.g. when the car is cornering).
The main-beam assistant uses the yaw rate to improve evaluation when the car corners. The DSC sensor is
underneath the driver's seat. For safety reasons, cars with active front steering have a second DSC sensor
underneath the front passenger's seat.
[for further information, please refer to SI Technology (SBT) 34 02 03 042]
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Image sensor
The image sensor is a special camera for detecting light sources.
The image sensor transmits images to the control unit for the main-beam assistant.
The images are carried by an LVDS data line (LVDS: Low Voltage Differential Signalling).
The control unit for the main-beam assistant analyses the images.
The image sensor and the control unit are installed in a common housing and can only be supplied as a unit.
SBT Main-beam assistant E60, E61, E63, E64, E65, E66, E70, E90, E91, E92, E93
BMW AG - TIS
07.02.2013 13:23
Issue status (12/2007) Valid only until next DVD is issued
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