Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Disconnect fan plug from PCB (top left marked FAN)
Measurement:
Test 1:
Measure the resistance between the two grey wires at the disconnected plug.
Resistance should be approximately 50Ω.
Test 2:
Measure the resistance between one of the grey wires at the disconnected plug to a suitable earth point.
Resistance should be greater than 1MΩ (or O.L).
Measure the resistance between the two grey wires at the disconnected plug.
Resistance should be approximately 50Ω.
Test 2:
Measure the resistance between one of the grey wires at the disconnected plug to a suitable earth point.
Resistance should be greater than 1MΩ (or O.L).
Isolate as per TOPs P4
and refit as necessary