A system and method to warn that a child has been left unattended in the vehicle when the ignition is off. The system includes a sensing device to detect if a child is in the infant seat, an ignition detection device to detect that the ignition is off, a delay timer to provide a certain period of time for the caregiver to remove the child from the car seat or put the child in the infant/booster seat and then to generate an alarm, a speaker to sound the alarm, and a switching assembly to detect when the dome light goes on, or if the dome light is operable.