I had a problem with our middle burner no longer lighting, and it turned out to be the wire had come off on the back side of the sparker knob. It doesn't require any tools to get to it. First you have to twist the burners counter-clockwise so that you can lift them up and unplug that end of the wire, and set them out of the way. Then you just have to remove the top by lightly squeezing/twisting the brackets that hold it in place, and then you can slide the top backwards (it feels spring loaded) until it releases in the front and you can lift it off.
"A good traveler has no fixed plans, and is not intent on arriving." - Lao Tzu