Could it be a bad fuse? We do not see fuses under the cooktop.

SOURCE: knob not working and some burners not heating

The switch under that knob is bad.  It's called an infinite switch.  As far as the elements go, first thing to check is for proper voltage (220) to the cooktop.  Let me know what you find.

SOURCE: jenn air electric cooktop

first, disable power to cooktop. next, replace either the mangled burner or the entire unit (after initial inspection leads to a logical prognosis)...sorry.

SOURCE: Cooktop will not get hot

wire conections to ct from house wiring may be loose check conectors

SOURCE: How do I remove my electric cooktop...the conduit

On link below is a install manual It might not be yours but they are all pretty much the same. It will tell you how to install. You just do the reverse to remove.

Also you do not un wire the cooktop from the cooktop but from the junction box in the wall. Please make sure the breaker is turned off before you un-wire it.

http://www.jennair.com/assets/product/JEI0430ADS_Installation%20Instruction_EN.pdf

Testimonial: "Thankyou very much for the link"

SOURCE: hello- Will In Houston Teas

Hi,
Here is a tip that I wrote that will help figure out why the burner spark keeps on clicking...

Gas Range Repair Burners Keep on Clicking
http://www.fixya.com/support/r4033033-gas_range_repair_burners_keep_clicking

heatman101