where is the rear window defroster relay located in a 2004 Toyota Four Runner, would this also control the rear wiper arm?
Try something simple: just open and re-close the rear window. The window has a safety switch that keeps the wiper, washer and heater from working if the window is open. The window settles down (from opening and closing the hatch) over time the window settling triggers the switch. If you open and re-close the window it resets the switch and everything works again. My 2003 4 Runner does this over time. I just open it and re-close it to fix the problem.