Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Gain access to the fan
Disconnect the wires from the fan motor and earth points

Measurement:

Test 1:
Measure the resistance between the terminals of the fan motor.
Resistance should be approximately 40 Ohms.
Test 2:
Measure the resistance between one end of the fan motor and the fan earth connection.
Resistance should be at least 1M Ohm.