Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove one of the wires from the lockout reset switch

Measurement:

Measure the resistance across the terminals of the lockout reset switch.
Resistance should be open circuit.
Operate reset switch.
Resistance should now be short circuit.
Release switch.
Resistance should now be open circuit.