Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove connector X14 from the PCB

Measurement:

Test 1:
Carry out a resistance test between the brown and blue leads of connector X14.
Expect a resistance of approx 740 ohms.
Test 2:
Measure the resistance between the brown and the earth wire of connector X14.
Resistance should be at least 1M Ohm.