The preceding posts should be corrected as indicated in the new [June 17, 2012] introduction to the first post above. Also, Stu Jackson and Maine Sail may have puzzled over my assertion that on the Guest battery selector the Common terminal lay behind the Both switch position. In fact, it doesn't. It lies (at least on the type of Guest battery selector switch aboard Hali), counter-intuitively, behind the "2" switch position.