AC Fan Not Working? Common Problems and Solutions Explained If your AC is running but the fan isn’t spinning, it’s a clear sign something is wrong, and ignoring it can lead to serious system damage. One of the most common causes is a faulty capacitor. The capacitor provides the initial boost needed to start the fan motor. If it fails, you may hear a humming sound, but the fan won’t spin at all. Read the full guide here: https://callgunnys.com/blog/ac-fan-not-spinning/