Rain Sensor Description and Operation

Description

The rain-sensing wiper system is a wiper system that, in addition to the normal wiper functions of OFF, MIST, manual LOW, manual HIGH and WASH, provides automatic control of AUTO INTERMITTENT, AUTO LOW and AUTO HIGH speeds. When the ignition switch is in the ON position, the rain sensor is activated.

System Features

Basic principle: A light beam emitted by a diode is totally reflected from the outside of the windshield and then received by a photodiode. If there is water on the outside of the windshield, the beam is optically separated, and the amount of remaining beam is measured by the photodiode. When there is no water on the windshield, the light is fully reflected, so the degree of beam loss indicates how wet the glass surface is.Wiper ECU operation: The rain sensor sends a signal, and the rain sensor detects rainwater and transmits it to the wiper ECU. The wiper ECU sends a command, and the ECU controls the wiper motor according to the signal. Contact influence: The rain sensor may malfunction due to the following conditions.

• Contamination of the measuring surface.
• Air bubbles between the windshield and the contact surface of the coupling pad.
• Movement of the coupling pad due to vibration.
• Damaged wiper blade.

Operating conditions: If the engine is started with the wiper switch in AUTO, the rain sensor is activated after one wipe cycle to inform the driver that the system is in AUTO mode.