blower motor or resistor?

Well this morning I was driving along with the heat on when I heard a low rumbling/grinding sound:confused: Experimented a little and the noise went away when I turned the fan off. It seemed to be present at all the speeds, just got quieter at each lesser speed!
Later in the morning I lost all fan speeds.

I am leaning towards a bad motor because of the noise but is it possible it was only the resistor that went?

Thanks for any help

i would look into a blower motor, couple of things to take into consideration, age of the motor. couple things i have ran into at my work is mice filling the "squirrel cage" with nuts and junk like that which could give you your noise but i only come across that on customers that live out in woody areas. if your resistor was bad you would still have high speed, but no other speeds.