Model #E30EC65ESS3, this five burner electric cook top heated properly, but the hot surface indicator for the center burner was no longer working. This cook top uses electronic infinite switches instead of the more traditional mechanical switches to provide temperature control of each surface burner. But figuring the hot surface circuit was going to be the same, it was just a couple quick checks to figure out which part had failed.
Cook tops and ranges that have glass or ceramic cooking surfaces will often have a hot surface indicator light to visually show when the surface is still hot. In some cases there will be only one light, and in others, each element will have it's own light. Because the ribbon type elements used in these smooth top units will heat the surface as well as the pots and pans placed on them, the top will remain hot for quite some time even after the elements have been turned off.
The indicator lights are activated by a switch connected to a temperature probe mounted on the element. When the element is turned on high, the probe can be seen as a line running through the center of the element. This probe will expand and close a set of switch contacts mounted within the element electrical connector. These switch contacts complete the electrical circuit to the hot surface light. Once the surface unit cools down, the probe will return to it's normal size again opening the switch contacts and opening the electrical circuit.
On this unit, the normal indicator light is part of the electronic element control board. The board provides power to the element much like a mechanical infinite switch, but also has a display to show the temperature that has been selected. When the element is turned off, the display will show 'HO' as long as the surface remains hot. Because the center element indicator wasn't working, I simply turned the element on long enough to force the probe to expand and close the switch contacts. A quick resistance check with the harness unplugged from the control board showed the switch closed, which leaves the infinite control board as the part that has failed.
After replacing the element control board in this cook top, everything was once again displaying as expected.