This is probably a really insipid question, but I can't seem to figure it out. My courtesy lights no longer turn on when I unlock the vehicle or when I open the doors.

I took a small road trip yesterday and they were working when I left, but at some point during the trip that feature has been disabled. I had a back seat passenger that was playing with the lights in the back during the trip, but I cannot imagine that would have caused this problem. The lights work fine when I manually turn them on. All the doors are closed tightly.

Any thoughts? Am I missing something? My manual doesn't say anything about disabling courtesy lights.