The light switch is read as control over awareness — turning understanding on or off at will. A switch that does nothing is taken as feeling powerless to change a mood.
Does the traditional reading fit your dream, or did it mean something else to you?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.