Re: S54T09X1GB/06 F/D 8703
Can’t help with a wiring diagram i’m afraid but IIRC the softener solenoid should be energised while the machine is filling in which case its simply a case of tracking down the loss of neutral to the aquastop…
Does the supply go via the flood switch btw? If so the harness and switch there would be my first port of call, other than that it’s a case of identifying the correct output on the pcb and checking for continuity through the aquastop at the connector there. If that’s ok then it only really leaves the pcb?
HTH?