[TOMT] Movie Memory From the 1970s

In 1977 or 1978, I went to a drive in theater in California with a friend and his family. I can't remember the name of the movie, but there was a scene where the main character, a little boy, was in a diner or a truck stop diner and the waitress was playing a song on the jukebox or singing a song and I remember it had something to do with "sunny side up" The movie may have been about the little boy looking for his missing dog. (It was not Benji or Poco) I swear this was a real movie. I remember this scene vividly, but for the life of me I can't find it or the name of it anywhere. Been trying for years! Does anyone remember this?