Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Hinge down the PCB housing
Remove the fan harness connector from the fan
Remove the 3 way connector from the top of the PCB (blue and red wires)
Remove the 3 way connector from the top of the PCB (blue and red wires)
Observation:
Test 1:
Measure the resistance across the red and blue pins on the disconnected 3 way connector.
Open circuit expected.
Test 2:
Measure the resistance between the red wire of the disconnected 3 way connector and a suitable earth point.
Expected resistance above 1 MOhm
Measure the resistance across the red and blue pins on the disconnected 3 way connector.
Open circuit expected.
Test 2:
Measure the resistance between the red wire of the disconnected 3 way connector and a suitable earth point.
Expected resistance above 1 MOhm
Isolate as per TOPs P4
and refit as necessary