Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove connector CN9 from the PCB

Measurement:

Test 1:
Measure the resistance between pin 3 (brown)
and pin 4 (brown) on connector CN9.
Expected resistance approximately 80 ohms.
Test 2: Resistance to Earth
Measure the resistance between pin 3 (brown)
and a suitable Earth point.
Expected resistance greater than 1 MOhm.