Wiper and Washer Systems: Description and Operation

The wiper and washer system consists of the following components:
^ windshield wiper mounting arm and pivot shaft
^ pivot arms
^ windshield wiper blades
^ windshield washer reservoir
^ windshield washer pump
^ windshield wiper motor
^ [1][2][3][4]Generic Electronic Module (GEM)
^ multi-function switch
^ windshield washer nozzle and bracket

PRINCIPLES OF OPERATION

Multifunction Wipers
The front wiper/washer feature controls the speed of the front windshield wipers and the amount of washer fluid sprayed on the front windshield when requested by the customer. There are five (5) wiper modes: OFF, LOW, HIGH, INTERVAL, and WASH.

Washers
When the GEM detects the ignition switch circuits are in RUN or ACC states, and the GEM detects a WASH request from the wiper delay/wash circuits, the GEM will activate the washer pump relay circuit for as long as the request is present up to 10 seconds.

Activation of the washer pump when in INTERVAL or OFF is delayed until a wash request is active for a minimum amount of time. In this scenario, the wash request must be present continuously for at least 210 ms. This allows a wash request that is present for less than 210 ms, to provide additional functionality by initiating a single wipe, called "mist wipe". The mist wipe function is a single wipe at low speed without activating the washer motor.

When in LOW or HIGH, any WASH request, regardless of the length of time it is present, will activate the washer pump. When in INTERVAL or OFF mode, upon deactivation of the washer motor, this feature shall provide two wipes at low speed before returning to the INTERVAL or OFF state as defined by the inputs. These additional wipes are provided to clear residual washer fluid from the front windshield.