11.4.3 System work principle
11.4.3.1 System operating principle
Headlamp operating principle
When the light combination switch is turned to the “headlamp” gear, the operating voltage is input
through a terminal No. 13 of the combination switch wire harness connector IP42, and the
headlamp relay is driven to close through control grounding of a terminal No. 16 of the wire
harness connector IP42 to turn on the headlamp. The headlamp supply voltage is transmitted to the
headlamp optical axis regulating switch as well as left and right headlamp optical axis regulating
motors; at this time, the signal voltage of the regulating motor can be changed by turning the
regulating switch up and down, thereby realizing the height regulating function of the headlamp.
Notes:
The regulating motor may not work or be damaged due to the frequently turning of the button.
When BCM (centralized controller) monitors that the voltage of a terminal No. 6 of a light
combination switch wire harness connector IP42 is less than 1V, which shows that the switch is in
"AUTO" (automatic transmission); at this time, the BCM shall monitor a signal from an ambient
light sensor; if the ambient illumination is not strong, the BCM will input power supply from a
terminal No. 5 of the IP49, a headlamp relay is driven to close by controlling grounding through a
terminal No. 7 of a wire harness connector IP50, so that the headlamp automatically turns on;
when the ambient illumination is strengthened, the MCB cuts off the power supply output, so as to
realize that the headlamp automatically turns off.
When the light combination switch is turned to the high beam position, the operating voltage is
input through the terminal No. 7 of the combination switch wire harness connector IP42, and the
high beam relay is driven to close through control grounding of the terminal No. 16 of the wire
harness connector IP42 to turn on the high beam; and at the same time, the high beam provides.
Voltage is sent to the instrument to turn on the high beam indicator lamp therein.
Notes:
The working voltage of high beam lamp relay is from the headlamp power supply circuit.
Position lamp operating principle
When the light combination switch is turned to the "headlamp" gear, the switch signal is output to
a terminal No. 26 of the BCM wire harness connector IP50 through a terminal No. 14 of the wire
harness connector IP42 of the combination switch, and the operating voltage turns on all position
lamps through BCM wire harness connector position lamps passing through IP49-20 and IP49-10;
the operating voltage turns on left and right license plate lamps through the BCM wire harness
connector position lamps passing through IP49-8; and at the same time, the voltage is transmitted
to a back light regulating switch, and the brightness of the back light can be regulated through the
switch.
Front fog lamp operating principle
Coil driving power supply of the front fog lamp relay is from the terminal No. 8 of the IP49 of the
BCM. When the front fog lamp switch is switched off, the switch provides the grounding circuit to
drive the front fog lamp relay to close, and the operating voltage turns on the front fog lamp
through the relay. Meanwhile, this voltage is transmitted to the instrument.
Illuminate the front fog lamp indicator.
Rear fog lamp operating principle
Coil driving power supply of the rear fog lamp relay is from terminal No. 8 of the IP49 of the
BCM. After the rear fog lamp switch is closed, the rear fog lamp turns on. At the same time, this
voltage is sent to the instrument panel to light the front fog lamp indicator.
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