Abstract: A locking switch for electrical automobile systems connects and disconnects an automobile battery to the starter. The locking switch has two normally separated contact plates, one connected to a cable from the battery and the other being connected to a cable from the starter. A lock cam is mounted at the end of a cylinder lock, which is key-actuated. The lock cam carries a spring-loaded copper ball that rotates with the lock cam upon actuation by the key. The cam and ball can be moved from an open position on one stationary contact to a closed position, whereby the ball provides electrical contact between the two stationary contacts, thus completing the electrical circuit between the battery and the starter. Each stationary contact is provided with a semispherical indentation in which the ball is received in the open position, thereby providing a substantial contact area between the ball and each of the two stationary contacts.