A simulation approach is developed to define the control strategies of a new ‘intelligent’ component of the engine cooling system: the variable speed fan system. The paper describes the way each component of the cooling loop is characterized by geometric data or test results to create a one dimensional network of the cooling circuit. Then, comparison with experimental confirms the relevance of the models and their limits. At last, several types of control strategies are evaluated on a simplified driving cycle. This study finally determines the necessary tests to obtain a correct model, able to adapt control strategies for any vehicle.