Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove connector X21 from the PCB

Measurement:

Test 1:
Measure the resistance between the brown and blue wires.
Expect a resistance of 1 Mohm or greater.
Test 2:
Measure the resistance between the brown and earth wires.
Expect a resistance of approximately 0.8 Mohm or greater.
Are the resistances measured as expected?