Wiper and Washer Systems: Description and Operation

WIPERS AND WASHERS

PRINCIPLES OF OPERATION

The front and rear window wipers and washers are controlled by the multifunction switch. Both of the wiper motors are supplied an ignition voltage from the SJB and a battery voltage from the bussed electrical center (BEC). The multifunction switch (digital) supplies the appropriate signal to the wiper motors as determined by the multifunction switch position.

The following components are integrated into the windshield wiper motor: the windshield wiper motor module, high/low speed relay, run/park relay, Hall-effect sensor and the washer pump relay. The following components are integrated into the rear wiper motor: rear wiper motor module, run/park relay and the washer pump relay.

High Speed Windshield Wipers
High speed is activated when the multifunction switch supplies ground to the windshield wiper motor module inputs. The windshield wiper motor module then supplies ground to the run/park relay coil and the high/low relay coil, activating the relay with voltage supplied from the ignition switch (ON/ACC) through the SJB. When the windshield wiper motor module receives voltage from the run/park relay, it removes ground from the run/park sensor, deactivating it. The windshield wiper motor continues to operate from voltage connected through the run/park relay until the Hall-effect senses the magnet in the motor. When the Hall effect senses the magnet in the motor, the windshield wiper motor returns to the park position, the internal run/park relay grounds the windshield wiper motor module input and the windshield wiper motor module removes ground from the windshield wiper high/low relay coil, deactivating the high/low relay and windshield wiper motor. The windshield wiper motor module continues to cycle the windshield wipers until the inputs from the multifunction switch are changed from the high speed position.

Low Speed Windshield Wipers
Low speed is activated when the multifunction switch supplies a specific ground to the speed inputs of the windshield wiper motor module. The windshield wiper motor module then supplies ground to only the windshield wiper run/park relay coil, activating it. When the windshield wiper run/park relay is activated, the deactivated windshield high/low relay connects voltage to the windshield wiper motor low input, activating the wiper motor. The windshield wiper motor module continues to operate the windshield wiper motor in the same manner as in high speed, but in low speed with the wiper motor connected to the low speed input.

Intermittent Speed Windshield Wipers
The intermittent wiper speed is activated with grounds controlled by the multifunction switch inputs to the windshield wiper motor module. The windshield wiper motor module then activates the windshield wiper run/park relay coil and switches voltage through the windshield wiper high/low relay. The high/low relay remains deactivated, supplying the voltage to the wiper motor low speed input and activates the windshield wiper motor. When the windshield wiper motor module receives the grounded input, the motor continues to operate until Hall-effect sensor senses the wiper motor magnet, which turns off the run/park sensor output to the windshield wiper run/park software, deactivating the relay and disconnecting voltage to the wiper motor. The windshield wipers remain parked until the windshield wiper motor module completes a time-out and then repeats the intermittent windshield wiper cycle.

Default Mode
The windshield wiper motor defaults to this mode when the run/park sensor does not sense the Hall-effect magnet inside the wiper motor. This can be caused by an obstruction of the windshield wipers or a binding linkage. The windshield wiper motor continues to operate in a high/low speed condition for a period of 60 seconds.

Washer System
The windshield washer is activated by the internal wiper motor module when it receives a ground from the multifunction switch between the washer input. Dependent on the correct ground, the internal wiper motor module activates the windshield washer relay (internal) by grounding the respective relay coil. When the relay is activated, it connects voltage to the washer pump.