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 M12 from the PCB

Measurement:

Measure the resistance between the brown wire "H" and the blue wire "G" at M12 on the PCB.
Resistance should be short circuit (zero resistance)