Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove connector CN1 from the PCB

Measurement:

Test 1.
Measure for resistance across blue and brown at CN1.
Expected resistance approximately 270 kΩ.
Test 2.
Measure for resistance across brown and green/yellow (earth) at CN1.
Expected resistance greater than 1MΩ (or O.L.).