Hi.

You are looking at bad bridge element or the infinite switch.

To determine which one you need to remove the cooktop from the cabinet, take the screws around the perimeter out and lift the top.

With power off check the L/R element first visually for brakes and then using the multimeter, check the continuity at the element.

If you don't see anything wrong with the element, turn on the power (only if you feel OK to do the "life"test), turn on the burner switch and check for 230v at the element in question.

Reading 230v - replace the element.

No voltage - replace the infinite switch.

The bridge element Part number: AP2826918