Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove the connector from the fan
Remove the 3 pin connector from the PCB
Remove the 6 pin connector from the PCB

Observation:

Measure the resistance across each of the wires running from the fan connector to the appropriate PCB connector.
Expect continuity / zero resistance on each of the wires.
Also visually inspect the condition of the harness.
Are the harness checks satisfactory?