blower motor

hey guys...96 deville blower motor stopped working, just got from a friend about a week ago and it worked fine, he replaced the motor couple years ago so its not very old seem to have power to the plug but does blow, any way i can test to see if the fan is bad or a relay somewhere or maybe the controls on the dash? u can hear the vent open and close when u change from vent heat to defrost please help gettin cold here in PA