Power Window not working
 

I have a 2009 Ford Explorer. The drivers control switch for the front passenger window is not working. The passenger switch for the passenger window works fine. If the problem is a broken wire in the harness going into the driver's side door, what GAUGE wire do I use to splice it back together? I have a soldering iron and some wire, but I don't want to cause an electrical fire by using the wrong size wire. Thank you!

Before planning anything, you must first verify that is the problem. You will not be able to see the problem. To pull the covering away from the door and pillar can be a stinker of a job and A wiring diagram would be very helpful, but the only other way to prove what we suspect is to open up the pass side door and look at the color of the wires that come back to the driver's side master switch and use a long piece of wire to jump each color wire one at a time that come from the pass side sw and go to the driver's side master sw.
If one of the wires is broken and you jump the right one the window will work correctly from the master sw.
I want to assure you this job is no picnic and you might want to have a qualified shop handle it.

Thank you. I took the driver's side switch control box apart and put it back together, and somehow everything is working fine now. Must have been a loose connection at the switch.

Glad you found the problem. Thanks for the update.