In this paper, we propose a filtering algorithm for simultaneously estimating the mode, input and state of hidden mode switched linear stochastic systems with unknown inputs. Using a multiple-model approach with a bank of linear input and state filters for each mode, our algorithm relies on the ability to find the most probable model as a mode estimate, which we show is possible with input and state filters by identifying a key property, that a particular residual signal we call generalized innovation is a Gaussian white noise. We also provide an asymptotic analysis for the proposed algorithm and provide sufficient conditions for asymptotically achieving convergence to the true model (consistency), or to the "closest" model according to an information-theoretic measure (convergence). A simulation example of intention-aware vehicles at an intersection is given to demonstrate the effectiveness of our approach. K E Y W O R D S nonlinear filtering, state and input estimation, switched systems, uncertain systems 1.1 Literature review The filtering problem of hidden mode hybrid systems without unknown inputs have been extensively studied (eg, papers 7-9 and references therein), especially in the context of target tracking applications, along with their convergence and National Science Foundation grant CNS-1943545.