Diagnosing a Whirlpool GJC3634 smoothtop range

We bought a Whirlpool cooktop for last year's kitchen remodel. Our cooktop, the GJC3634RP03, has a white surface, which means a lot of elbow-grease (usually mine) and baking soda whenever we cook, but there are no drip pans. It's not an induction range, so we can use all kinds of cookware. The heat settings need some getting used to. It's not perfect, but overall we're satisfied.

At least we were, until the central part of the center-rear element went kaput. Here's the deal: the control can be set to heat up just the inner part ("single" I think it says) vs the entire, larger concentric disk ("dual"). With the inner burner dead, setting the burner to "single" gives you nothing, whereas "dual" gives you doughnut-shaped heating. The latter almost works OK for pancakes, but it's harder to get the heat right.

A look at the wiring diagram convinced me that it could not possibly be the normal-vs-simmer control, which would have affected both elements equally. I immediately suspected the burner, just because, but the control is an equal-opportunity point of failure. The range didn't go into the kitchen 'til October, but we took delivery in June or July, so we're out of warranty already.

Nothing for it but to do a little disassembly. I started by turning off the breaker supplying electricity to the range. I verified that it was indeed off by turning one of the burners "on" and noting that the power indicator didn't light up (it does so, instantly, when power is connected). Sticking my hand under the range, I levered it part-way out of its cutout and took a look. It turns out that the smooth white top is attached to the guts of the stove with ten screws (three along the front, three on the back[unverified], and two on each side). I supported the front edge with a skillet, as shown in the photo at left, and removed the screws (one position is circled in magenta in the detail).

With 7 screws (3 in front and 2 on each side) removed, you can lift the front edge of the stove and take a peek inside. In the photos, I lifted the surface just enough to see what was going on with the heating elements. The element of interest (the center rear) has three electrodes -- no surprise there -- indicated with magenta arrows in the detail.

At first, when I put the ohmmeter on the, uh, un-common electrodes (with gray/white and gray/black wires), it showed a dead short! Turns out it was an effect of the control; in the "off" position, it ties the un-common electrodes together. I verified this by switching the control to "single"/low and they no longer showed as a short. But just in case, I pulled each wire off when checking for continuity with the common electrode. One showed continuity and the other didn't. That's the smoking gun; it's the element rather than the control. Too bad; the element is about $100 whereas the control is about $40. Next step, ordering the element from Appliance Parts Pros (about $8 less than at Sears).