I have a 2002 Acura EL. From the master switch, rear left window goes up and down as it should. But it does not work at all from the rear left switch. I first suspected the issue is the switch. But when I plug the rear right switch in to rear left connector, it does not work either. And when I plug the rear left switch in to the rear right connector, it works fine. So we can rule out the switch.

Before I start tearing apart the door, anyone have any suggestion?

 

Another idea is a broken wire in the door conduit area of either the left rear door or the front driver door. Flexing of the wires over time causes them to break. I've had it happened twice and both times is was the driver's door area.