Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Disconnect connector marked X101 (grey connector)
from the Switchboard

Measurement:

Test 1:
Measure the resistance across the connections at the disconnected plug.
Resistance measured should be approximately 2000 Ohms (2 kOhms)
Test 2:
Measure the resistance across one of the connections at the disconnected plug to a suitable earth connection.
Resistance measured should be open circuit.