Whats the wiring situation for the rear wiper? When I first got this truck, it didn't have a wiper arm but I could hit the switch and watch the mount swing back and forth. Now I have a wiper arm (Thanks Tuxedo!) but upon hitting the switch nothing happens, although I can press up on the switch and the washer fluid sprayer works fine. Just no movement. Is the switch prone to corrosion/failure like the hazard switch issue? Or is there a relay somewhere? I did check the fuse and its good.

1989 Dodge Raider V6
2001 Jeep Wrangler 4.0L
2008 Toyota 4-Runner SR5 4wd