I haven't had to fuss with mine yet (the one in the picture is a spare). If it is giving you problems, and not just misaligned, you can take it off, take it apart and clean it. Even though the selector switch has a gasket between it's two halves, dirt may still get into it and mess with the electrical connections. Just take it apart, get all the dust and dirt out of it, clean the connections and put it back together. If the electrical contacts aren't worn out you should be good to go.