Set Appliance State:

Set Multimeter to Resistance Set meter to measure resistance
Isolate Mains Power to appliance as per TOPs P4
Remove connector CN1 from DBI PCB

Measurement:

Test 1 :
Measure the resistance between pin 1 (red) and pin 5 (blue) on connector CN1
Expect a resistance of 1Mohm or greater
Test 2 :
Measure the resistance between pin 1 (red) and the earth wire on connector CN1
Expect a resistance of 1Mohm or greater.