Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Disconnect connector X3 and from the PCB

Measurement:

Test 1:
Measure resistance between the spark generator neutral (marked 10.2 on X4) and live (marked 10.1 on X3).
Expect greater than 1M Ohm.
Disconnect connector X4 from the PCB.
Test 2:
Measure the resistance between the spark generator live (marked 10.1 on X3) and a suitable earth point.
Expect greater than 1M Ohm.
Test 3:
Measure the resistance between the spark generator neutral (marked 10.2 on X4) and a suitable earth point.
Expect greater than 1M Ohm.