[Dave_S.]

I had this same problem and I traced it to a stuck switch with is part of the passenger side tailgate latch mechanism. The switch is designed to not allow the window to roll up unless the tailgate is closed. The fix was easy, simply spray wd40 all over the latch mechanism. You can do this from the inside if you have the tailgate trim panels off and the window is up, or from the outside if the window is stuck in the down position. (The switch inside the door jam is only for the lights and does not have anything to do with the operation of the window).
I'm guessing this stuck switch is the primary cause for this common problem.

In my case the window started intermittently not going up, it would go down fine, but when commended to go up, nothing - no electrical draw as the lights did not dim. You could sometimes open and close the tailgate and it would work again. It didn't matter if you were trying to operate the window from the dash switch or the key in the tailgate. Since spraying the latch with WD40, it now operates perfectly again. Thank God - this was really a PITA when it wasn't working.