Two of the ignitors (left side) on my cooktop are sparking properly. The other two ignitors (right side) are arcing at the base of the ceramic electrode.

My first step in trouble shooting was to swap the wires from right to left and left to right. And sure enough, the problem went from the left side to the right side. So my first impression was that one side of the spark module has a weak spark.

But then I got to wondering how the spark on the malfunctioning side could arc from the base of the electrode to the cooktop body. The air gap at the base of the electrode is much greater than the air gap between the electrode tip and the burner. That means that the spark on the malfunctioning side must actually be stronger than the working side because it has greater resistance.

Does anyone have any experience with ignitors sparking below the burner?