The interior light in my Sonata 2013 wouldn't turn off when the car was running. I took apart the light and found that the switch contact had worn a hole in the plastic so that it was making contact when in the middle position. I used some crazy glue to fill in the hole and is seems to be working now.

contacts with the switch removed. You can see the hole that I filled with Crazy glue

3 way switch installed in interior light