This paper presents an approach of modeling variability of automotive system architectures using function nets, views and feature diagrams. A function net models an architecture hierarchically and views are used to omit parts of such a model to focus on certain functionalities. In combination with feature diagrams that describe valid variants, the concepts of feature and variant views are introduced to model architectural variants. The relationship between views, variants and the underlying complete architectural model is discussed. Methodological aspects that come along with this approach are considered.