Despite the efforts of organizations, institutions, car makers, car seat manufacturers and consumer groups to alert parents about the safety threat heatstroke poses for young children left in hot vehicles the number of victims each year is increasing. In fact, one child dies from heatstroke nearly every 10 days from being left in a hot vehicle. For this reason, this work focuses on using current technology to help prevent such fatalities. We have used intelligent agents, which have proved to be rather efficient since they can monitor, coordinate events and disseminate information as well as communicate with each other. We have developed a multi-agent architecture that detects when young children left in child safety seats inside vehicles are at high risk of heatstroke and sends an alert message to the driver's smartphone. The design of the architecture using the INGENIAS methodology is described.