In my attempt to repair my central AC unit, what could possibly be the issue if the central AC unit does not run and all I hear from the outside central AC unit is a "humming" sound? I replaced the fan motor because when I first heard the "humming" sound coming from the outside AC unit I noticed that the fan was very hot to a touch. Rather than continue to replace any other electrical parts, such as the Contactor or Capacitor, would anyone know from his or her knowledge and past experience what might be the problem? Thank You