Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove connector X12 from the PCB
Remove the 3 wire connector from the fan

Measurement:

Measure the resistance of each of the wires in the harness running between X12 and the Fan AC connector.
Expect continuity / zero resistance.
Also visually inspect the condition of the harness.
Are the resistances as expected and is the harness in good condition?