Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Disconnect connector X7 from the PCB
Measurement:
Test 1:
Measure the resistance between the black and blue wires on X7 connector.
Resistance should be approximately 25 - 50 Ohms.
Test 2:
Measure the resistance between the black wire on X7 connector to a suitable earth point.
Resistance should be greater than 1M Ohm.
Test 3:
Measure the resistance between the blue wire on X7 connector to a suitable earth point.
Resistance should be greater than 1M Ohm.
Measure the resistance between the black and blue wires on X7 connector.
Resistance should be approximately 25 - 50 Ohms.
Test 2:
Measure the resistance between the black wire on X7 connector to a suitable earth point.
Resistance should be greater than 1M Ohm.
Test 3:
Measure the resistance between the blue wire on X7 connector to a suitable earth point.
Resistance should be greater than 1M Ohm.
Isolate as per TOPs P4
and refit as necessary