Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove connector CN12 from the PCB

Measurement:

Test 1.
Measure for resistance across pins 69 & 70 of connector CN12.
Expected resistance approximately 0.8 kOhms.
Test 2 - Resistance to Earth:
Measure the resistance between pin 69 on connector CN12 and a suitable Earth point.
Expected resistance greater than 1 MOhm.