Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove X3 connector from the PCB

Measurement:

Test 1. Measure for resistance across pins 2 (Blue) and 3 (Black) of connector X3.
Expected resistance 9.1 kOhms.
Test 2. Measure for resistance across pin 2 (Blue) and Earth (Main terminal block).
Expected resistance Open Circuit.
Test 3. Measure for resistance across pin 3 (Black) and Earth (Main terminal block).
Expected resistance Open Circuit.