Fujitsu ARU-RLF Disassembly Instructions Manual page 6

If the float switch is the
problem the pump will
need to be removed first to
gain access to the float
switch. Once the pump is
removed you will see the 2
screws that hold the float screws that hold the float
switch in place. Remove
the 2 screws to remove the
float switch from the unit.
You can now replace the
float switch or the pump.