Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Disconnect plug marked CON9 from the PCB

Measurement:

Test 1:
Measure the resistance across the two yellow wires
of the disconnected plug.
Resistance should be open circuit.
Test 2:
While pushing the reset switch down repeat test 1.
Resistance should now be short circuit (zero resistance).