The uplifting chorus can mask the meaning in this song, which is about a woman who is leaving her man because she needs time to find herself. She asks him to "leave a light on" for her, meaning to wait for her return, but that's a lot to ask.
The lyric was written by Ellen Shipley, who said in a Songfacts interview
: "That was very specifically a feeling that I had about people going on their own way. Even though they love someone, it's just time for them to find themselves. It's pretty easy.
In that story, she had to go find herself in order to come back and be with this person. Oftentimes people leave because they're not done growing up, and in this case she feels like she will be back so she says, "Leave the light on for me, the porch light, because I'm going to come back." But there's always the doubt that he'll be there.
It was more important for her to find herself first, which is my feeling in life. And if you're in a relationship and something feels wrong, if you break it down to not the guy or not the woman but in yourself, it usually has to do with finding yourself and coming into a relationship as a full authentic person. So, I tried to do that with the lyric."