My a/c blower fan is making a loud buzzing noise when I turn it up passed half power. I just bought this car from a family member. It is in wonderful shape. All of the maintenance has be done over the years. There are no issues other than the a/c fan doesn't have but one or two speeds, slow and very slow. When I turn the power up to 3/4 speed and full speed there is no difference in how hard it blows AND the buzzing noise that sounds like it's coming from the passenger side under the dashboard gets really loud. What do you think is wrong? Could it be the blower itself or maybe the blower resistor? I thought if it was the blower then it possibly could be something in the blower itself keeping the fan from turning past a certain speed. I don't know.