Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Disconnect high voltage plug from fan
Disconnect connector X3 from the PCB

Measurement:

Check for continuity (zero resistance) of the blue and brown wires running from the 240V fan plug to connector X3 on the PCB.
Check the harness wires and plugs are in good overall condition.