Why won't the interior lights come on when the door is opened?

The interior lights work of you switch them on, but we can't figure out how to make it so that they automatically cone on when she opens the door. So I don't think it's a fuse.

well,its most likely a 3 position switch! ON - OFF - DOOR are you sure it's not in the off position when the doors are being opened?try setting the switch to door or auto!