Power windows do not operate some times. The power door locks and power mirrors operate all the time. When the windows do not operate the interior dome light and the exterior bed light on the cab roof do not work either. The next day, everything works great - then the next day same problem.
All the circuits that are working intermittently are controlled thru the GEM.
Your shop will first verify the associated fuses are all working. Next they’ll remove a door card and measure the voltage at the power-input at the window motor. If the voltage is ok and the window doesn’t move then the problem is the motor or the window-associated parts. If the voltage is incorrect they’ll trace the circuit back to the switch. If the switch is ok then it must be something between the switch and the window, likely either chaffed insulation where the wires go from the door to the body in the door hinge area, or the control circuity mentioned above. My suggestion, next truck ask for manual windows.