already replaced infinite switch what next

I have a Kitchenaid slide-in electric range. model kesc300 Both left burners blew. One was the dual element. I replaced the infinite switch for the dual burner (the wires looked pretty beat up). The question is should I replace the other infinite switch and get new wiring? If so, which wire harness should I replace? the one that links both switches together or the one that goes deeper into system? or is there another issue I should be concerned about.:rolleyes: