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)
Locate and remove M5 connector from the PCB

Measurement:

Measure the resistance between terminals 27 (Brown) and 31 (Blue) of the disconnected M5 plug.
Resistance should be open circuit.