Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Remove connector CN2 from the PCB
Measurement:
Test 1.
Measure for resistance across pins 1 (blue) and 4 (brown) of CN2.
Expected resistance approximately 160Ω or greater.
Test 2.
Measure for resistance across pin 4 (brown) and a suitable earth connection.
Expected resistance greater than 1MΩ (or O.L.)
Measure for resistance across pins 1 (blue) and 4 (brown) of CN2.
Expected resistance approximately 160Ω or greater.
Test 2.
Measure for resistance across pin 4 (brown) and a suitable earth connection.
Expected resistance greater than 1MΩ (or O.L.)
Isolate as per TOPs P4
and refit as necessary