A method and apparatus for evaluating window regulators of the type having a reversible electric motor connected to a slide/carrier plate by means of cables. The apparatus comprises a first transducer such as a piezoelectric accelerometer or a laser for generating a first signal quantity related to periodic noise produced by the motor during operation thereof, a second transducer such as a piezoelectric accelerometer for producing a second signal quantity representing transient noise produced by irregularities in the slide/carrier plate assembly during travel of the carrier plate along the slide, and a processor for decoding the first and second waveforms and using data derived therefrom as a basis for identifying unacceptably noisy window regulator assemblies. The method comprises placing the window regulators on a test fixture, operating the window regulator with a simulated glass load, and generating and processing the first and second signal quantities as described above.