Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove connector X1C from the PCB

Measurement:

Test 1:
Measure the resistance between pin 1 (brown) and pin 2 (blue) of connector X1C.
Expect approximately 160 Ohms.
Test 2:
Measure the resistance between pin 1 (brown) and pin 3 (earth) of connector X1C.
Expect greater than 1MOhm or O.L.
Are the resistances measured as expected?