Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove connector CN2 from the PCB

Measurement:

Check for continuity (zero resistance) between the brown wire at Pin 4 on CN2 to L at the pump and between the blue wire at Pin 1 on CN2 to N at the pump.
Inspect the harness and plug / connections are in good overall condition.