You need to check the infinite switch output.
Using the multimeter check if there is 240VAC between H1 and H2 of the infinite switch when it's on.
Be careful with "hot" appliance.
If there is no 240VAC - replace the switch
Part number: WB24T10063
If you'll have the proper voltage - replace the element
Part number: WB30T10095
Here are the breakdown diagrams and Cooktop replacement parts for General Electric JP989SK1SS Electric range | AppliancePartsPros.com
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