SAFARI BSVI - SERVICE MANUAL

ELECTRICAL 171 27. RAIN LIGHT SENSOR SYSTEM (IF APPLICABLE) A. RAIN LIGHT SENSOR DESCRIPTION: RAIN SENSOR: It is an optical system, which operates in the infrared wavelength range. The sensor houses 6 infra-red LED’s forming a segment of a circle around a receiver diode. Any rain drops landing on the windscreen in the sensitive area of the sensor cause spontaneous imbalance in the reflection, which results in production of a voltage with the clocking frequency of the LED’s. An electronic analyzer and output detect these brief deviations as digital pulses. The pulse duration is a measure of droplet LIGHT SENSOR: The Light Sensor is an optical system. It operates with three photo diodes, FW, IR and AL that have different characteristics. The three diodes measure independently from each other. Diode AL (Ambient Light) is used to measure the ambient light above the vehicle with a relative wide apex angle. This receiver reacts to light in the human eye wave range (visible light). Diode IR (Infra-Red) is used to measure the ambient light perpendicular to the windshield with a relative wide apex angle. This receiver reacts to light in infrared light wave range. Diode FW (Forward) is used to measure the light in the direction of the car movement with a relative small apex angle. This receiver reacts to light in the human eye wave range (visible light). BLOCK DIAGRAM The rain light sensor is connected via LIN (local interconnect network)-bus to BCM. The BCM controls the wiper motor in automatic mode according to the commands received from the rain sensor. The RLS (Rain light sensor) measures the ambient luminosity. A combination of the measured luminosity values are send on the LIN bus. This brightness is provide to the BCM as frequency (Analog data). The BCM includes an algorithm to control the headlamps status of the vehicle. Combi-switch position, rain sensor sensitivity and park position of the wiper motor information is provide to the RLS via LIN communication.