If they are corrupt, just run the installer, and do a repair, and that should fix them.

Otherwise. If you want to adjust them, and want to know the name of the wave file, go to the FSX/P3D\Captain_Sim\737\sound folder, and the FSX/P3D\SimObjects\Airplanes\CS_B737-200\sound folder, double click on each .wav file so you can find which ones are the ones you want to adjust.