Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Gain access to PCB (use Insulation Mat as required)
Disconnect plug marked X7 from the PCB

Measurement:

Check for short circuit across the terminals at the disconnected plug X7 between the brown and blue (1 & 2).
Resistances approx 8 MOhms.