Body Electrical System > Windshield Wiper/Washer > Rain Sensor

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 - Rainsensing Windshield Wiper System

Multifunction switch position	Rainsensor operating mode	Sensor action
MIST	MIST	Mist is controlled by the column switch. The sensor has no affect on this function
OFF	OFF	If not already parked, wiper motor runs in low speed until blades are in the depressed park position.
AUTOMATIC Automatic mode has 5 SENSITIVITY settings. This is further defined in par 84.	AUTOMATIC	AUTOMATIC Automatic INT/speed control. The sensitvity to raindrop accumulation on the windshield is set by the MULTIFUNCTION SWITCH sensitivity adjustment.
LOW SPEED	MANUAL	Wiper motor runs continuously in low speed, for example 45 wipes/minute. The sensor has no affect on this function
HI SPEED	MANUAL	Wiper motor runs continuously in high speed, for example 60 wipes/minute. The sensor has no affect on this function
WASH - DEMAND WASHER SW ≥ 0.6 SEC	WASH	If washer sw on after 0.6 sec then wipes during 2.5 to 3.8 sec. The rain sensor enables the wipers and controls the after wipes.
WASH - DEMAND WASHER SW < 0.6 SEC	WASH	If washer sw on less than 0.2 to 0.6 sec then once wipes

Off Mode

With the wipe switch in the OFF position and the ignition switch in the ON positions, the Rainsensor is considered to be in "OFF" mode. In this mode, the sensor commands the wiper to be off.

The Rainsensor monitors the state of the windshield during OFF mode so that knowledge of the state of the windshield is present when the MULTIFUNCTION 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 Mode

When the MULTIFUNCTION SWITCH is moved to AUTO position and the ignition switch is in the RUN or ACCESSORY positions, the Rainsensor is considered to be in "AUTOMATIC" mode. Once a single "Instant wipe" as described in par 8.8 has occurred, the wipers remain at "Innerwiper/park" untill the Rainsensor determines that the dwell time at that position is appropriate for the amount of precipitation on the windshield, considering the driver input from the switch SENSITIVITY setting. After the dwell time the Rainsensor provides input to the wiper motor to activate the wipers to clear the preciptation from the windshield.

Automatic Int

For all Automatic Int operations the Rainsensor commands the wipers to operate in LOW SPEED for one wipe, followed by a variable dwell period in the inner wipe position.

Automatic Low

Automatic Low SPEED operation is utilized when the amount of precipitation imping on the windshield exceeds the Automatic Int TO Automatic Low threshold. This threshold includes sufficient hysterisis 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 imping on the windshield exceeds the Automatic Low to Automatic High threshold. This threshold includes sufficient hysterisis to prevent cycling between Automatic Low to Automatic High operation with a steady amount of precipitation accumulation on the windshield.

Wash Mode

The Rainsensor monitors the MULTIFUNCTION SWITCH to determine if the wash function is selected. Rainsensor 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 Rainsensor 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.