Set Appliance State:

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

Measurement:

Test 1:
Measure the resistance across the
two fan terminals.
Resistance should be approximately
45-60 Ohms.
Test 2:
Measure the resistance between each
fan terminal, in turn, to a suitable earth point.
Resistance on each test should be
greater than 1M Ohm.