Rain Sensor Description and Operation

Description

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

System Features

Operating Principle: The infrared beam emitted by the LED is totally reflected from the outside surface of the windshield and then received by the photodiode. If water is present on the outside of the windshield, the beam is optically split, and the remaining beam intensity is measured by the photodiode. Since water on the windshield means the beam is not totally reflected, the degree of beam loss indicates the degree of wetness of the glass surface.Wiper ECU Operation: The rain sensor sends a signal to the wiper ECU as it detects rainwater. The wiper ECU controls the wiper motor based on this 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 Condition: If the engine is started with the wiper switch in AUTO mode, the rain sensor is activated after one wiper cycle to inform the driver that the system is in AUTO mode.