Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove electrical connections to fan assembly

Measurement:

Test 1.
Measure the resistance across the fan terminals.
Expected resistance approximately 40 ohms.
Test 2.
Measure the resistance between one fan terminal and a suitable earth connection.
Expected resistance greater than 1Mohm.