Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Gain access to small PCB on the rear cover (water sensor PCB)

Measurement:

Measure for resistance across pins 5 and 7
on the water sensor PCB 8 way connector.
Expected resistance 10 ohms or less.
Is the resistance measured as expected?