PRE-RELEASE
Main beam, detailed description
| Main beam, detailed description |
| Main beam |
Halogen headlamps
The light switch (10) is connected to BCM. When the switch is in position 2, BCM sends the bus message "Dipped beam button active ON". The dipswitch is integrated in CIM. When it is moved to its rear position (2), CIM sends the bus message "Main beam, stalk active ON".
BCM receives the bus message "Main beam, stalk active ON" and sends the bus message "Main beam indicator active ON" to MIU (540). MIU lights the lamp (47g) that indicates that main beam is lit.
While the ignition key is turned to the START position (+50), main beam is off. Main beam lights again once the engine has started or once the ignition key has been turned to the ON position.
Xenon headlamp, US/CA
The light switch (10) is connected to BCM. When the switch is in position 2, BCM sends the bus message "Dipped beam button active ON". The dipswitch is integrated in CIM. When it is moved to its rear position (2), CIM sends the bus message "Main beam, stalk active ON".
The bus message "Main beam, lever active ON" is used by UEC, which switches to main beam in the headlamp optics by supplying B+ from control module pins 17 and 21 to headlamp pin 2 while the outputs for dipped beam are active.
When voltage is supplied to headlamp pin 2, the screen in front of the Xenon lamp drops down to produce a main beam image.
Each headlamp is grounded in the body on pin 1.
BCM receives the bus message "Main beam, stalk active" and sends the bus message "Main beam indicator active" to MIU (540). MIU lights the lamp (47g) that indicates that main beam is lit.
While the ignition key is turned to the START position (+50), main beam is off. Main beam lights again once the engine has started or once the ignition key has been turned to the ON position.
Xenon headlamp, other markets
The light switch (10) is connected to BCM. When the switch is in position 2, BCM sends the bus message "Dipped beam button active ON". The dipswitch is integrated in CIM. When it is moved to its rear position (2), CIM sends the bus message "Main beam, stalk active ON".
The bus message "Main beam, lever active ON" is used by UEC, which activates main beam in the headlamp optics by supplying B+ from control module pins 17 and 21 to headlamp pin 2 while the outputs for dipped beam are active (control module pins 16 and 25). Each headlamp is grounded in the body on pin 1.
When voltage is supplied to headlamp pin 2, the screen in front of the Xenon lamp drops down to produce a main beam image.
The H7 bulb is lit while the Xenon lamp produces a main beam image.
BCM receives the bus message "Main beam, stalk active" and sends the bus message "Main beam indicator active" to MIU (540). MIU lights the lamp (47g) that indicates that main beam is lit.
While the ignition key is turned to the START position (+50), main beam is off. Main beam lights again once the engine has started or once the ignition key has been turned to the ON position.
Main beam logic variants:
| Type of headlamp | Market | Description |
| Halogen | US/CA/MX | The H11 dipped beam lamp shines together with the H7 main beam lamp. |
| Halogen | Others | The H7 dipped beam lamp shines together with the H9 main beam lamp. |
| Xenon | US/CA/MX | The xenon bulb shines at main beam |
| Xenon | Others | The Xenon lamp shines with a main beam image together with the H7 halogen lamp |
Filament monitor
In the event of filament breakage in a bulb, the electrical centre (UEC) detects the drop in current, regards it as a fault and sends a bus message which is used to display a message in SID. UEC supplies B+ to the lamps from a semiconductor output. If bulb output exceeds 100 W, a DTC is generated in UEC and a message is displayed in SID.
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When changing a bulb, use one with the right output otherwise the components could be damaged. |
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| Headlamp flasher |
The headlamp flasher, a “main beam flash”, can be activated regardless of the position of the ignition switch and light switch by using the dipswitch (215) to the left of the steering wheel.
Halogen headlamps
When the dipswitch is moved to the spring-back position, CIM sends the bus message "Flash to pass active ON". UEC lights main beam by supplying voltage from control module pins 17 and 21 to pin 2 of the headlamps (11FL/FR).
At the same time, UEC sends the bus message "Main beam active", which is used by MIU to light up the main beam symbol.
The halogen main beam bulb lights regardless of the position of the ignition key.
Xenon headlamp, US/CA/MX
When the dipped/main beam dipswitch is moved to the spring-back position, CIM transmits the bus message "Flash to pass active ON". UEC transmits the bus message "Main beam active ON", which is used by MIU to illuminate the main beam symbol. UEC uses the bus message and activates main beam.US: The xenon lamp lights regardless of the position of the ignition key. The screens are lowered and the optics assume main beam mode.
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UEC lights the xenon lamp by supplying B+ from control module pin 3 to headlamp pins 25 and 16. The optics assume main beam mode when B+ is suppled from control module pin X to headlamp pin 2.
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Xenon headlamps, other markets
When the dipswitch is moved to the spring-back position, CIM sends the bus message "Flash to pass active ON". UEC sends the bus message "Main beam active ON", which is used by MIU to light the main beam symbol. UEC uses the bus message from CIM to light main beam. Which lamps are used depends on whether dipped beam is lit.The main beam lamp (H7) lights regardless of the position of the ignition key. The dipped beam screen is lowered, the xenon lamp lights if the ignition is ON and the main light switch is in the "parking light" or "lights off" (dipped beam on) position.
Dipped beam off:
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The UEC turns on main beam by supplying B+ voltage from control module pins 17 and 21 to pin 2 of the headlamps (663FL/FR). When headlamp pin 2 is supplied voltage, the H7 main beam lamp (11) lights.
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Dipped beam on:
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UEC lights the main beam lamps and the dipped beam screens are lowered when B+ voltage is supplied from control module pins 17 and 21 to headlamp (663FL/FR) pin 2 as well as from 25 and 16 to headlamp (663FL/FR) pin 3 for the already lit dipped beam.
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