Principles of Operation

PRINCIPLES OF OPERATION

The wiper motors receive inputs from the following:
- multifunction switch
- lighting control module (LCM)
- ignition switch
- battery junction box (BJB)

The following components are integrated in to the wiper motors:
- windshield wiper motor module
- hi/lo speed relay
- run/park sensor (Hall effect)
- washer pump relay

High Speed Windshield Wipers
High speed operation is activated when the multifunction switch supplies a ground to the wiper motor module input. This ground is applied to the run/park and high/low relays contained in the wiper motor electronics, activating the relays and providing high speed operation. The windshield wiper motor module continues to cycle the windshield wiper in high speed operation until the inputs from the multifunction switch are changed from the high speed position.

Low Speed Windshield Wipers
Low speed operation is activated when the multifunction switch supplies a specific ground to the inputs of the windshield wiper motor module. The windshield wiper motor module then supplies a ground to the windshield wiper run/park relay coil, activating it. The run/park relay and high/low relay are contained in the wiper motor electronics. 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 five intermittent wiper dwell times are activated with grounds controlled by the multifunction switch inputs to the windshield wiper motor module. When in intermittent mode of operation, the wiper motor operates in low speed. Once the windshield wiper motor module receives the necessary inputs from the multifunction switch, it 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 Hall sensor signal is lost. This can be caused by an obstruction of the windshield wipers, a binding linkage or an electronics concern. The motor will operate in either low or high speeds; intermittent operation is not available. The windshield wipers will not correctly park in this situation and must be manually walked down the glass by changing the multifunction switch input to the wiper motor module (OFF to Low).

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