The likely hood of a solid state electronic device such as the GEM to fail after 6 months of good use is rare, unless outside factors are incorporated. The GEM is a body control module (located behind the radio to the left), it controls the the accessory delay relay (allowing windows to function until the door is open), horn chirp when locked, dome light when unlocked and door is closed, wiper speed, for 2x4 it converts the speed sensor signal to a usable signal for the cluster, etc.
Did you check all three pins for voltage when the button is pushed at the window connector?
Try this which has helped many of a ranger, explorer, and mustang owner:
Smack the motor with a hammer and try it. NO JOKE.
Quality Engineer (Electronics) for Kia Motors
University of Tennessee Electrical Engineering Graduate
2000 XLT 2.5L A/T