Tailgate Window Will Not Close From Tailgate Key Switch, Otherwise Operates

With ignition switch on, and tailgate door open, place key switch in "UP" position. Using a grounded 12-volt test lamp, probe Lt. Blue wire at key switch. If lamp does not light, replace key switch. If lamp lights, probe Lt. Blue wire at cut-out switch.
If lamp does not light, check for open Lt. Blue wire between key switch and cut-out switch. If lamp lights, check for open in Lt. Blue wire between cut-out switch and window motor. If wire is okay, replace cut-out switch.