The current simulation models of EV and ICE Vehicles are well known in industry for their use in estimating the fuel economy or Range benefits because of controller calibrations and component sizing. However, there is a gap in understanding the behavior of accessories such as HVAC, power steering and other such auxiliary loads and the energy losses associated with them. Impact of thermal behavior of electronics on vehicle range also needs to be studied in detail. These kinds of studies help OEM and tier 1 manufactures in improving their design concepts significantly with minimum cost and development time. Hence, the focus of this study is on building simulation models of thermal, electrical, traction and control circuits of a typical electric vehicle. These models are then integrated, and analysis is performed to understand vehicle system level performance metrics. Individual models have been built for HVAC and thermal circuit of on EV in AMESim, HV and LV electrical power distribution in Simulink and for vehicle powertrain using powertrainblockset in Simulink. The aim of this paper is to demonstrate the importance of simulation models that capture both traction, accessories and energy consumption split between them. Different challenges in building, integrating and cosimulation of models, impact of model fidelities on runtimes and accuracy of results have been discussed. Modelling aspects related to HVAC, cooling and heating loops of electronics devices, battery and traction control, are also included. Finally, the results over a typical drive cycle are presented.