2001 Yukon XL front blower motor problem

[JSLayton]

My wife told me approx a week ago that the front vents had stopped working. I disconnected the front blower motor and tested the voltage coming out of the connector and it appeared that the voltage was around 12 volts when the fan was off and climbed to 13.5-14 volts when the fan was turned on high. Is this normal or am I not testing this correctly? Since I was getting voltage but the motor wasn't turning, I assumed the problem was the motor and I purchased a used one from a junkyard and it still won't work. Could the resistor be the problem? I just thought that, since I was getting voltage, that the resistor should be ok. Am I missing something?