Multifunction Switch
WARNING: This page is about a different car, the 2010 Ford Pickup, 2010 Ford F550 Super Duty, 2010 Ford F450 Super Duty, and 2010 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
The multifunction switch controls the various components (high-beam headlamps, flash-to-pass, turn signal and windshield wiper) by grounding certain Smart Junction Box (SJB) circuits and wiper motor circuits. When the SJB detects the specific ground, it sends a voltage to the appropriate component to activate it. The SJB controls the high-beam headlamps, the flash-to-pass and the turn signals. The high-beam headlamp and the turn signal portion are normally open switches that close when activated. The flash-to-pass switch is a momentary contact switch that grounds the SJB high-beam headlamp circuit. The windshield wipe and wash functions are controlled directly by the multifunction switch, wiper and washer motor.