Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove connector X1 from the main PCB
Remove the electrical plug from the pump

Measurement:

Check for continuity (zero resistance) between the central blue and brown wires of X1, in turn, to the corresponding wire at the pump plug (refer to picture).
Also visually inspect the condition of the wiring and connectors.