Evaluation of defects in parts made by additive manufacturing methods such as selective laser melting is always one of the important issues for manufacturers of these types of parts. Along with the development of their manufacturing methods, the defect inspection methods in such parts are also being developed and completed. Previously, researchers have shown the effectiveness of modal tests, which are vibration-based methods, to identify defects in parts and structures made of metal, plastic, composite, and concrete. But for additive manufacturing parts, the development of modal methods with the application of defect detection is in the early stages of research. The first research in this field has been done with an additively manufactured part in the shape of a beam. The smallness of additive manufacturing parts and structures, due to the limitation of the build chamber of the printing machine, brings the challenge of high frequency excitation of the part in the modal test. In this article, in a step forward, by modal analysis and comparing the modal properties of healthy and defective steel plates made by selective laser melting, defect identification from one-dimensional space to two-dimensional space has been done, up to the level of defect locating and severity assessment. The defect in the defective plate is intentionally created in the form of a crack on the surface of the plate, and methods based on frequency change and mode shape change including mode shape curvature and modal strain energy have been used to identify and locate the defect