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Light switch, (10)

Light switch, (10)

Location

Light switch, (10)

Light switch unit (684), manual headlamp levelling


Light switch unit (684), automatic headlamp levelling (AHL)


Main task

Use to select light setting off, parking, or headlamps. BCM sends the switch status on the bus.

Type

The rotary switch has three positions for the headlamps. The circuit is also equipped with two internal diagnostic resistors.

When the switch is turned all the way to the right (lights off), the switch contacts are open and only the two internal diagnostic resistors (1.8 kΩ each) are connected between each connection and ground. If the switch is turned one setting to the left, (parking lights) pin 2 is grounded. With an additional turn to the left (headlamps) pin 1 is grounded.

The light switch also has LEDs to light the symbols and knob.

Connection

The light switch is directly grounded to the body. The 2 pins of the lighting knob are supplied 10.2 V separately via a 1.2 kΩ (parking light setting) and a 1.5 kΩ (headlamp setting) resistor integrated in BCM. Voltage between each pin and ground is 0 V when the circuit is closed to ground and approx. 6 V (parking light setting) and 5.5 V (headlamp setting) when it is open. If the control module reads 10.2 V, it will interpret it as a break. The LEDs are grounded internally and are supplied with PWM-regulated voltage from BCM.

Pin No.
Signal type
Description
1 Headlamps To BCM. Grounded 2 steps from knob's right end position (when knob points straight up)
2 Parking lights To BCM. Grounded 1 step from knob's right end position
3 Lighting From BCM, power supply with PWM to LEDs
6 Ground Supply