The compressor on my frigidaire dehumidifier runs continuosly. The on/off switch works the blower but it won’t shut off the compressor.Is the circuit board shot?
Here are the parts. You will ahve to choose the correct unit from the Matching Models Numbers.
Parts for FAD704DUD - AppliancePartsPros.com
Looks like there is not many parts available for it.
Below is the wiring diagram.
http://manuals.frigidaire.com/prodinfo_pdf/Edison/202026690020.pdf
Yes it sounds like the control board is toast.
Perhaps the on the board compressor relay’s contacts are welded together.
It is also possible that the electronics that close the relay are bad and always energizing it.