Abstract: An automobile alarm comprising a pair of self latching relay devices one or the other of which, but not both, must operate within a predetermined time after turning the ignition switch on or hot wiring around the switch. The depression of the horn ring within the predetermined time disables the alarm and connects the normal circuits of the car for normal operation. The failure to depress the horn ring within the predetermined time latches the horn or an auxiliary alarm device on and prevents starting of the car. A timing device for unlatching the horn after a predetermined alarm time is also shown.