Set Appliance State:

Set Multimeter to Resistance Set meter to measure resistance
Isolate Mains Power to appliance as per TOPs P4
Disconnect connector 2 (right) from the ignition PCB

Measurement:

Test 1:
Measure the resistance between the blue wire on connector 1 and a suitable earth point.
Resistance should be at least 1M Ohm.
Test 2:
Measure the resistance between the brown wire on connector 1 and a suitable earth point.
Resistance should be at least 1M Ohm.