Rear Wiper won't shut off

I just picked up my new to me wk. I cant for the life of me figure out how to turn off the rear wiper. I have tried every position on that switch arm and it just keeps going randomly. It's only the rear wiper that's moving, it's like it's possessed.



I tried searching the web and this forum, but I cant find anything.



Anyone know what this is? Relay?



Thanks



05 wk hemi