Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance

Measurement:

Test 1:
Measure the resistance between the live and neutral wires on connector X12.
Expect a resistance of 1MOhm or greater.
Test 2:
Measure the resistance between the live and earth wires on connector X12.
Expect a resistance of 1Mohm or greater.
Are the resistances measured as expected?