Rain Sensor: Description and Operation

Description

The Rain sensing windshield wiper system is a wiper system that, in addition to providing normal wiper functions off, mist, manual low speed, manual high speed, and wash, provides automatic control of automatic intermittent, automatic low, and automatic high speeds.
When the ignition key is in the ON position, the rain sensor (A) will be activated.






Operating Modes - Rain Sensing Windshield Wiper System





Off Mode
With the wipe switch in the OFF position and the ignition switch in the ON positions, the rain sensor is considered to be in "OFF" mode. In this mode, the sensor commands the wiper to be off.
The rain sensor monitors the state of the windshield during OFF mode so that knowledge of the state of the windshield is present when the Multi Function Switch is moved to any SENSITIVITY setting. This optimizes the performance of the sensor when moving from the OFF condition to an AUTOMATIC mode. The algorithm assumes the nominal sensitivity setting when in the OFF mode.

Automatic Low
AUTOMATIC LOW SPEED operation is utilized when the amount of precipitation impinge on the windshield exceeds the AUTOMATIC INT TO AUTOMATIC LOW threshold. This threshold includes sufficient hysterics to prevent cycling between AUTOMATIC INT and AUTOMATIC LOW SPEED operation with a steady amount of precipitation accumulation on the windshield.

Automatic High
AUTOMATIC HIGH SPEED operation is utilized when the amount of precipitation impinge on the windshield exceeds the AUTOMATIC LOW to AUTOMATIC HIGH threshold. This threshold includes sufficient hysterics to prevent cycling between AUTOMATIC LOW to AUTOMATIC HIGH operation with a steady amount of precipitation accumulation on the windshield.

Wash Mode
The rain sensor monitors the Multi Function Switch to determine if the wash Function is selected. rain sensor enables the wiper motor to run in low speed during the wash mode and performs follow up wipes during 2.5 to 3.8 sec.

Manual Mode
The rain sensor determines when a manual mode such as manual low, Mist, Off or manual high is selected. The column switch performs these modes and the rain sensor has no affect.