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 low voltage connector X7 from the PCB

Measurement:

Measure the resistance between the white wires on the end of X7, marked 8.1 and 8.2.
Short circuit expected.