In this study; first of all, finite element undamped modal analysis was performed on one of the automotive rear lamp lenses and were obtained natural frequencies and mode shapes. Then, Frequency Response Functions (FRF) of an automotive rear lamp lens, made of polymethyl methacrylate (PMMA) material,were obtained by using Impact Hammer Test Methods. Two different test methods can be used in the modal test by using impact hammer and accelerometer.One of them,- To move the hammer on the measuring points- Another is to move the accelerometer on the measuring points.In both test methods, dynamic characteristics of the structure, natural frequencies, damping ratios and mode shapes were obtained. Damping ratios were calculated from the FRF’s by using the Half Power Method. Finite Element Analysis(FEA) results and test results were compared and the best test method was determined.The results obtained from both test methods were compared with the finite element undamped modal analysis results and the results are below.- For FEA results and roving hammer test results error rates respectively;14,597% and 16,781%,- For FEA results and roving accelerometer test results error rates respectively; 9,006% and 9,643%.