Set Appliance State:

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

Measurement:

In turn measure the resistance of the blue and brown wires between the spark generator connector and the PCB connection.
Expect continuity / zero resistance.
Also visually inspect the harness to ensure there are no shorts or damaged insulation.