Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove connectors X15 and X13 from the PCB

Measurement:

Test 1:
Measure the resistance between the two wires at connector X13.
Expect approximately 6.1 Kohms or O.L.
Test 2:
Measure the resistance between the middle terminal of connector X13 and the wire at connector X15.
Expect approximately 6.1 Kohms or O.L.
Are the resistances as expected?