Model #JES9750BAS, this range with coil elements had been operating fine, and still did with the exception of the right rear burner. This element would no longer heat and it didn't the position of the selector knob. The indicator pilot light, however, did illuminate when the knob was in the on position. Because this unit has cartridge
style elements, the customer did try to swap the two, but the failure remained in the right rear postion indicating a problem with the body of the range itself.
Most ranges and cook tops use an infinite switch to control the temperature of the surface elements. The infinite switch will turn on and off both the L1 and L2 sides of the 240vac and will also switch on an indicator pilot light to show when the switch is in the on position. Due to the simplicity of the usual heating circuit, most situations where the element is not heating can be reduced to either the element, the element receptacle (coil style element only), and the infinite switch. A voltage check of these components can quickly determine which item has failed.
This particular range has an added component as part of the heating circuit that from my opinion looks like an additional safety feature, but it too can fail. Looking at the sample wiring diagram, the L2 output from the infinite switch no longer goes straight to the element, but instead connects to the common terminal of a relay mounted under the cook top. This relay is driven by the L1 output from the infinite switch pilot circuit, thus the relay contacts will only close, when the infinite switch is in the on position. With the contacts closed, the L2 current will now pass through the relay and on to the element.
Using my meter to check the infinite switch, I was able to verify it's operation and did find the appropriate voltages at each of the output terminals. And because the element can be checked using substitution trouble shooting (I swapped the cartridges) I knew the element was good. That left the relay as the most likely problem, but I needed to remove the cook top to verify its operation. Once I had access to it, a resistance check of the relay coil indicated an open circuit. This relay had failed (BTW there are four relays is this unit so you can swap them around and see if the symptom moves just to be sure of you diagnosis).
With the top removed, I replaced the failed relay with a new factory fresh relay, and once everything was back together, the right rear element (along with the others) was working great.