Remember, the three connections [ 8, 9, 11 ] are ground-paths from the coil to the DIS, then to the mount, where the system's 12v at the coil is allowed to go to ground and complete the charging circuit...when the grounds are broken at the transistor blocks, the circuits are opened, discharging the coils/collapsing the fields and charging the plugs. Also remember that without a reliable ground path from the base of the DIS itself and back to the battery, the system can and/or fail outright.