A method for detecting whether the stator in a vehicle alternator has a turn-to-turn short circuit. The method includes determining an output current or voltage signal of the alternator, where the output current or voltage signal includes a ripple current frequency as a result of an AC-to-DC conversion. The method determines the speed of the alternator and a current output of the alternator. The method then determines the ripple current frequency of the alternator from the alternator speed, and determines a winding frequency from the ripple current frequency. The method performs an FFT analysis on the voltage and current signal, determines an amplitude of the winding frequency and compares the amplitude of the winding frequency to a predetermined amplitude, where if the difference exceeds a predetermined threshold, a turn-to-turn short circuit is likely occurring.