How'd you go with this? I put up with no passenger window for almost 2 years before I finally pulled back all the wiring in my drivers door. Found 2 completely snapped wires and one that had split insulation.
Cut and re-soldered the wires with a bit of extra length so the soldered joints aren't flexing each time the door opens and closes.
Now both my windows work, along with the door lock / unlock button which only unlocked before the fix!
Definately worth the hour or two to fix properly!