Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove connector CN22 from the PCB

Measurement:

Test 1.
Measure the resistances between the pins on connector CN22.
Test 2.
Measure the resistance between pin 1 on connector CN22 to a suitable earth point.
Expect a resistance of greater than 1 MOhm for each test.
Note.
A reading of O.L is acceptable as this is greater than 1 MOhm.