Washer Pump Relay (Integral)
WARNING: This page is about a different car, the 2005 Mercury Mountaineer and 2005 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.
Test the rear window wiper motor internal washer relay function by measuring the voltage between wiper motor (4) component side pin 5 (7), and ground. When wash command input pin 6 (7) is grounded, measured voltage should read 10 volts or greater.