To learn more about your unit first see whether the unit is receiving power. Check to see your breaker is turned on and that there is power coming out of the breaker (use a volt/ohm meter and measure for 115 volts or 220 volts depending on the units requirements.) Fujitsu has code lights that light up to tell you the status of the unit and gives error codes. I assume the unit is dead and there status lights are not lit up.
Next check for power at the outdoor unit with the volt/ohm meter. The outdoor unit will hav a disconnect box on the wall. Some have fuses which may be blown, some have breakers, and some have no fuses or breakers but do have a shorting bar with a handle that you pull straight out to disconnect power going to the outdoor unit. Once you have opened the cover of the unit you can tell which kind of disconnect you have. Remove the cover or pull the disconnect bar. You then will have the power circuits exposed and can measure to see if the unit is getting power.
Next, in the case of mini splits, there is sometime a indoor power switch to disconnect power to the indoor unit. The power for it comes from the outdoor unit. Make sure it is turned on. Sometimes kids play around and throw switches and don't know what they are doing and kill the power to the indoor part of your unit. If you are unsure if the indoor unit is getting power, you can remove the indoor cover by prying off the cover, then unscrew the phillips screw on the right of the panel to expose the incoming power terminals and measure for power actually being at the unit.
Lastly if you have power to the outdoor unit but no power to the indoor unit and there is no problem with the indoor disconnect, go back to the outdoor unit and check the fuses to see if any are blown. They are located inside the outdoor unit. You will have to remove the outdoor cover and screens to get to them. At this point you should have a repair manual with information on where the fuses are.
You may be getting over your head at this point and will best need to get a repair person with experience.
Most people are not capable of doing his last step.
on Aug 10, 2019