A single dead burner can be caused by three things; the likliest first:
1. A bad socket. Burner prongs must be securely gripped by the spring loaded socket. Sockets fatigue with age and heat and fail to connect at all on only for a short time. The result is a dead burner.
Gummed Up Socket
2. A bad infinite switch. If the other burners are fine, you know for sure that 220VAC is coming to the cooktop circuit. Use a multimeter to determine if 220 is present at the socket when the switch is on. If not, inspect the wiring under the top and at the switch. If all appears OK, verify that 220 is coming into the L1 and L2 on the switch. They will be the heavy red and black wires that jump to all four of the burner switches. If 220 is present there, replace the bad switch. Generally the output wires to the burner are marked H1 and H2 with P going to the indicator light.
Infinite Switches
3. If 220VAC is present at the socket and the burner fails to heat, obviously the burner or socket is bad. Replace it and if the old burner prongs are even slightly pitted or discolored, replace the socket also.
