Set Appliance State:

Set Multimeter to Resistance Set meter to measure resistance
Isolate Mains Power to appliance as per TOPs P4
Remove connector X3 from the PCB

Measurement:

Test 1:
Measure the resistance between the two wires on connector X3.
Expect a resistance of approximately 180 ohms or greater.
Test 2:
Measure between one of the wires on connector X3 and a suitable earth.
Expect a resistance of 1 MOhm or greater.
Are the resistances measured as expected?