奔驰

Rain/light sensor, component description

Illustrated on model 204.0

B38/2Rain/light sensor

P54.21-2696-04

Location

The rain/light sensor is located on the inside of the windshield, in

the area of the interior mirror.TaskTo measure the light intensity and degree of wetting of the windshield Via the degree of wetting of the windshield the

intermittent wipe of the wiper system (WSA) is controlled by two

sensitivity stages. Various functions of the interior illumination (IBL)

and exterior lights (ABL) are controlled automatically via the light intensity.

Function principle of rain sensor

Infrared light is beamed from the infrared transmitter unit (1) and is directed to the windshield (3).

The intensity of the light reflected at the windshield is measured by the infrared receiver unit (2).

If the windshield is dry in the area of the rain/light sensor (picture A), then the light is reflected

almost completely and the infrared receiver unit measures a high light intensity

If the windshield is wetted in the area of the rain/light sensor (picture B), then part of the light is

scattered from the windshield glass. As a result the intensity of the reflected light reduces and

the infrared receiver unit measures a lower light intensity.

The light intensity measured by the infrared receiver unit represents a measure for the degree of

wetting of the windshield. The smaller the measured light intensity the greater the degree of

wetting of the windshield.

P54.21-2413-03

iViatheoverheadcontrolpanelcontrolunit(N70)(withcode(414)

Power glass tilting/sliding sunroof) or the overhead control panel

electronics (N70/3) (without code (414) Power glass tilting/sliding

sunroof or with code (413) Panoramic glass sunroof with top sliding

sunroof) via the wiper/inside rearview mirror LIN the information is

looped through to the front SAM control unit with fuse and relay

module (N10/1).

戴姆勒 克莱斯勒股份公司版权所有 07-6-1 G/05/07。本WIS打印稿系统实时更新。第1页PDF created with pdfFactory Pro trial version