Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove connector J3 from the PCB

Measurement:

Test 1:
Measure the resistance between pins 1 and 2 on connector J3.
Expect approximately 160 ohms or greater.
Test 2:
Measure the resistance between pin 2 on connector J3 and a suitable earth.
Expect a resistance of 1 Mohm or greater.
(O.L is acceptable because this is greater than 1 Mohm)
Are the resistances measured as expected?