Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove both ends of the Fan harness from the Fan and PCB X8

Measurement:

Measure the resistance through each of the wires in the harness in turn.
Black = X8 Pin 3
Yellow = X8 Pin 4
Pink = X8 Pin 5