Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove Connector X20 from PCB (this is to ensure resistance readings are those of the fan not the pcb)

Measurement:

Check for short circuit across the fan terminals.
Leaving the plug on allows greater ease of testing.
Resistances approx. as follows;
Lead
Ohms
Blue & Black
19 MOhms
Blue & Grey
24 KOhms
Blue & Red
---

Blue and Red resistance changes constantly.
Therefore no reading given.
Note: Ensure a good connection is made.