Set Appliance State:

Set Multimeter to Resistance Set meter to measure resistance
Isolate Mains Power to appliance as per TOPs P4
Disconnect fan harness from fan

Measurement:

Check for continuity between each of the 5 wires on the fan harness.
Note:
The molex plugs do not have the same sequence of wires connected to them. Ensure each check is done same colour to colour.