Abstract: A child safety system is provided for motor vehicles in which the driver side door switch is electrically connected to the vehicle battery to activate the vehicle interior lighting system when the door is opened. In accordance with the present invention, a child safety seat is provided with an electrical circuit including a pressure sensitive switch with an alarm and a circuit with a connector for connection to the door switch circuit. The electrical circuit of the child safety seat is activated by the weight of a child on the pressure sensitive switch when the child is placed in the child safety seat. When the child safety seat is plugged into the vehicle driver side door circuit the alarm will be activated when the driver side door is opened with a child present in the safety seat.