Have you looked under stove top? Usually it lifts up so the connectors can be replaced. You could have a ton of burnt crap under there.
You would probably want 2 heat sticks if you stopped using the burner. One 2000w stick will boil 7 gallons ok, but it will take a long time to get there. The heat stick plus the burner is plenty.
Fermenter 1: Beer
Fermenter 2: Beer