Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Disconnect connector M3 from the PCB

Measurement:

Set Clock to OFF position.
Measure the resistance across connections 19 and 21 (black leads) at the disconnected connector.
Resistance should be open circuit.
Set Clock to ON position.
Measure the resistance across connections 19 and 21 (black leads) at the disconnected connector.
Resistance should be closed circuit.