Unless you have more dollars than sense, don't go throwing money at a problem trying to make it go away. In other words, don't replace the switch until you know it's bad.
Jordan's troubleshooting advice is right on. However I prefer troubleshooting with a meter. With a meter you can not only detect that there is power where you need it, you can also detect if there is a break in a wire somewhere or a short to ground. It can also be used to determine the integrity of your grounds.
