Originally Posted by t-type
Another possibility, if the switches check out OK, is I've seen a broken wire in the loom coming out of the driver'* side door. I've seen this more than once but its always been on the driver side door. It may be because that door opens and closes the most.
Yes. There is an interlock between the "local" switch on each door and the main panel on the driver'* door, so that you don't have a complete meltdown if the driver presses the Up button at the same instant the passenger presses his own Down button. When the driver'* panel is used, it momentarily cuts out the local switch at the door.
If you know how to remove the control panel on each door, I would suggest swapping the local switch on your rear door with the same one on the opposite door, and see if your problem changes sides. If it does, you have a problem with the local switch on the rear door; replace the offending one. If the problem does not change sides, it'* probably in the main panel on the driver'* door, or in the wiring between front and rear doors, and certainly I'd look real closely at that wiring bundle between door and pillar.
If you can find a junkyard donor, or even somebody else who'll loan you a driver'* door switch panel for half an hour, I'd swap in another switch panel first and see if that solves the problem before attacking the wiring harness.