If your Fujitsu air conditioner's operation light is blinking, it could mean a few different things. First, it may indicate that the unit is in defrost mode or that there is an error with the temperature setting. It can also signal a malfunction of the compressor motor or some other internal component. If this is happening, you should contact a professional HVAC technician to have them inspect and diagnose the issue as soon as possible so they can make any necessary repairs and get your system running smoothly again.