Main beam, detailed description

Main beam, detailed description

The bus message "Main beam, stalk active ON" is used by UEC, which lights main beam by supplying B+ voltage from control module pins 17 and 21 to pin 2 of the headlamps while the outputs for dipped beam are active. Each headlamp is grounded in the body on pin 1.

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, stalk active ON" is used by UEC, which lights main beam by supplying B+ voltage from control module pins 17 and 21 to pin 2 of the headlamps while the outputs for dipped beam are active. Each headlamp is grounded in the body on pin 1.

Pin 2 on the headlamp is fed with voltage for the main beam bulb (H7 bulb).

The H7 bulb is lit at the same time as the dipped beam Xenon lamp.

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, stalk active ON" is used by UEC, which lights main beam by supplying B+ voltage from control module pins 17 and 21 to pin 2 of the headlamps while the outputs for dipped beam are active. 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	All	The H7 dipped beam lamp shines together with the H7 main beam lamp.
Xenon	US/CA	The dipped beam Xenon lamp shines together with the H7 halogen bulb.
Xenon	Other	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.

Important

When changing a bulb, use one with the right output otherwise the components could be damaged.

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 right 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.

Xenon headlamp, US/CA

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.

Dipped beam on:

-	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.

Dipped beam off:

-	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.

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.

Dipped beam on:

-	UEC lights main beam by supply 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 screen in front of the Xenon lamp drops down to produce a main beam image and the H7 main beam lamp (11) lights.

Dipped beam off:

-	The UEC turns on main beam by supplying B+ voltage from control module pins 25 and 16 to pin 3 of the headlamps (663FL/FR) and from control module pins 17 and 21 to pin 2 of the headlamps (663FL/FR).