Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove connector A4 from the PCB

Measurement:

Test 1:
Measure the resistance between pins 3 and 6 on connector A4.
Expect a resistance of approximately 160 Ohms or greater.
Test 2:
Measure the resistance between pin 6 on connector A4 and a suitable earth.
Expect a resistance of 1 MOhm or greater.
Are the resistances measured as expected?