Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove connector CN14 from the PCB

Measurement:

Test 1.
Measure for resistance across brown & blue wires of connector CN14.
Expected resistance greater than 1MOhm (O.L is greater than 1MOhm).
Test 2 - Resistance to Earth:
Measure the resistance between brown wire on connector CN14 and a suitable Earth point.
Expected resistance greater than 1 MOhm (O.L is greater than 1MOhm).