Even if it is properly adjusted, if there is still some adjustment left, I would shift the switch a bit more in the direction it needs to go to work. The worst that can happen is it won't work then (it may need a bit more movement), or the switch won't shut off, which means you need to adjust between what it was, and what it is now.

Sometimes everything has just enough slop to keep things from working. Then you need to add just enough adjustment to accommodate for the slop.