Set Appliance State:

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

Measurement:

Test 1:
Measure the resistance across the disconnected leads.
Resistance should be approximately 45-80Ω.
Test 2:
Measure the resistance between either of the disconnect leads to a suitable earth point.
Resistance should be greater than 1MΩ.
Note:
Ensure a good connection is made, remove cover if necessary.