More Electric Vehicles (MEV) concept emphasizes the utilization of electrical systems instead of mechanical, hydraulic, and pneumatic systems to optimize vehicle fuel economy, emissions, performance, and reliability. In addition, the need for improvement in comfort, convenience, entertainment, safety, security, and communications necessitates more electric automotive systems. As a result, an electric power distribution system with larger capacity and more complex configuration is required to facilitate increasing electrical loads. Due to the environmental concerns, there is also a definite development towards new propulsion systems for the future cars in the form of Electric and Hybrid Electric Vehicles (EV & HEV). Most of these new electrical systems in advanced cars utilize power electronic converters and motor drives. In this paper, a modeling tool, which has been developed to study automotive systems using PSIM software, is presented. Different heat engines, transmissions, differentials, mechanical systems, control strategies, batteries, solar cells, and fuel cells have been modeled to enable simulation of vehicular systems. Suitability of the software package in design of different automotive systems will be explored as well.