Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove connector X2 from the main PCB
Disconnect the left hand electrical connection from the pump (mains supply)

Measurement:

Measure the resistance of each of the wires in the pump mains
supply harness as stated in the table below.
Pin on connector X2Mains supply plug
2 (Brown)Pin 1
3 (Blue) Pin 3
1 (Earth)Pin 2

Expect continuity / zero resistance on each test.
Also visually inspect the condition of the harness.