Rain/Light Sensor With Additional Functions, Component Description - GF54.21-P-6005GN
Model 166
as of Model year 2016
Model 292
Shown on Model 292
Location
The rain/light sensor with additional functions is located inside the windshield in the area of the inside rear-view mirror (A67).
Tasks
The rain/light sensor with additional functions is responsible for the following tasks:
- Reading in of signals
- Recording states
- Output of signals
Reading in of signals
The rain/light sensor with additional functions reads in the following signals from the SAM control unit (N10) via the roof LIN (LIN B13) among other things:
- Activation and sensitivity of rain sensor (B38/2b1)
- Outside temperature
- Vehicle speed
- Sensitivity of light sensor (B38/2b2)
Recording states
The rain/light sensor with additional functions records the following states in the windshield area:
- Background light intensity via the light sensor
- Degree of wetting over rain sensor
- Air humidity and temperature of inside of windshield through moisture/temperature sensor (B38/2b3)
Background light intensity
The light intensity of the vehicle's surroundings is measured by the light sensor.
Degree of wetting
The degree of wetting of the windshield is determined by the rain sensor using a transceiver distance. An infrared transmitter unit beams infrared light at a defined angle to the interior of the windshield, which is almost completely reflected onto an infrared receiver when the windshield is dry. If there are water droplets on the outer surface of the windshield, a considerable part of the light is diverted. The intensity of the reflected light is correspondingly lower and the reception signal of the infrared receiver is weakened. The lower the measured light intensity the higher the degree of wetting of the windshield.
Air humidity and temperature on inside of windshield
The humidity/temperature sensor measures the relative humidity and temperature directly at the inside of the windshield and uses this to determine the dew point temperature. The surface temperature on the windshield is also determined. The comparison with the dew point temperature enables any (impending) fogging of the windshield to be detected.
Output of signals
The rain/light sensor with additional functions sends the following signals via the roof LIN to the SAM control unit among other things:
- Requirements for exterior lights
- Background light intensity
| Wiring diagram for overhead control panel (OCP) control unit | PE54.21-P-2107-97NBA |