Set Appliance State:
Set Multimeter to Resistance 
Isolate Mains Power to appliance as per TOPs P4
Remove connector CN9 from the PCB
Remove connector CN9 from the PCB
Measurement:
Test 1 :
Measure the resistance between pin 2 (yellow) and pin 7 (blue) on connector CN9.
Expect continuity / zero resistance.
Test 2 :
Measure the resistances between pin 2 (yellow) and a suitable earth.
Expect a resistance of 1 Mohm or greater.
Measure the resistance between pin 2 (yellow) and pin 7 (blue) on connector CN9.
Expect continuity / zero resistance.
Test 2 :
Measure the resistances between pin 2 (yellow) and a suitable earth.
Expect a resistance of 1 Mohm or greater.
Isolate as per TOPs P4
and refit as necessary