Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove connector X2 from the PCB

Measurement:

Test 1:
Measure the resistance between the outer two brown and blue wires on connector X2
Expect a resistance of 1 MOhm or greater.
(O.L is acceptable because this is greater than 1MOhm)
Test 2:
Measure the resistance between one of the outer wires (it does not matter which) to a suitable earth.
Expect a resistance of 1 MOhm or greater.
(O.L is acceptable because this is greater than 1MOhm)
Are the resistances measured as expected?