Set Appliance State:
Set Multimeter to Resistance 
Isolate Mains Power to appliance as per TOPs P4
Measurement:
Remove Connector PL3 from the PCB.
Measure the resistance across the Red wire and the Blue wire on the disconnected connector.
The resistance measured should be approximately 850 ohms.
Measure the resistance across the Red wire and the Blue wire on the disconnected connector.
The resistance measured should be approximately 850 ohms.
Isolate as per TOPs P4
and refit as necessary