Combinatorial interaction testing (CIT) is a well-known testing strategy for software systems. We in- vestigate a new CIT approach which uses locating arrays as test suites, since this can enable not only fault detection but also fault identification. Existing studies on locating arrays do not take into account constraints over test pa- rameters. As real-world systems usually have such constraints, this approach has had limited applicability thus far. To cope with the problem, we introduce the notion of Constrained Locating Arrays (CLAs) which can deal with constraints and propose a method for automatically generating CLAs using an SMT solver.