As the size and complexity of the software in a truck grows, new ways of managing the development are needed. Numerous reports show how MDE can be successfully applied for automotive software development. We complement previous research by conducting a case study on the impact of model-based testing for verifying and validating the behaviour of a truck’s headlights. Our results are three-fold. First, we show how a model can be transferred from a model-in-the-loop setting to a hardware-in-the-loop via system simulation. Second, we supply an analysis of the shortcomings of the model that were found as the model was tested in more and more platform-specific settings. Third, our results show that the introduction of model-based testing practices will require organisational changes even if the used tools are familiar to the company.