Test a servo without Arduino
If you checked the servo coils for continuity, and it checks out, that should mean it's fine, unless it is somehow mechanically blocked from spinning.
 You could also have something between the PWM outputs and the servo itself, we can't be sure since we have neither a schematic nor a picture of your setup.
 Thirdly, just measuring a DC voltage on your PWM outputs doesn't have to mean they work properly. Observing them on an oscilloscope would tell you a lot more.
Did you actually open the servo and looked at the small controller board inside?  





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