These fans stop working all the time. It might just be dirty see if you can get into it clean and lube it. But do not expect to work for long if you do clean it and it starts working again. These type of fans always are a pain whether they are in a RC car or computer.
You know the guy that beat you at the last race? It was not because of his car, or motor, or battery, it is because he was a better driver. Now go practice so you can beat him.
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