In this paper, an approach for integrated behavior modeling and simulation within model-based electric/electronic-architecture (EEA) descriptions is presented. It leverages actor-oriented and UML state chart behavior modeling to address complex reactive systems. A key contribution is the aggregation of cross-layer behavior specified at the logical function architecture layer and at the hardware layer together with further properties of the EEA, such as the current consumption of electronic control units (ECUs), the underlying network topology and execution aspects of functions. The EEA and behavior modeling is done in the common industry tool PREEvision. Using these static descriptions, a unified simulation model is synthesized and executed using Ptolemy II, which extends a previously developed approach. In addition, a general concept to feed back the simulation data into PREEvision is briefly described e.g., to further evaluate the gained results. Finally, a proof-of-concept is presented using an Adaptive Cruise Control application.