Washer System
WARNING: This page is about a different car, the 2003 Ford Pickup, 2003 Ford F550 Super Duty, 2003 Ford F450 Super Duty, 2003 Ford Excursion, and 2003 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
The windshield washer or the rear window washer is activated by the internal wiper motor modules when it receives a ground from the multifunction switch between the washer inputs. Dependent on the correct ground, the internal wiper motor modules activates either the windshield washer or rear window washer relay (internal) by grounding the respective relay coil. When either relay is activated, it connects voltage to the washer pump while the deactivated relay provides ground to the washer pump. In this manner voltage polarity is reversible to achieve directional change of the washer pump and washer fluid.