no voltage to blower motor (300E)

[WANT '71 280SEL]

Is this a symptom of having a bad PBU? I tried resoldering about 75% of the connections on the back, but it still isn't working. I checked the voltage at the motor, (wires actually in the box), and my multimeter said 12 volts. My uncle said it's just enough to show it on the meter, but not turn the motor? I don't uderstand volts vs. amps. So does that mean it isn't getting any amps? The fact that the meter is telling me 12 makes me think at least that the fuses are good. I did check the fuses of course.
Thanks
David