You never posted the model number. What is it?

Gene.

The burners on your cooktop are very different. Thermador called them Star Burners. I found the part number for the Thermador spanner wrench designed specifically to use on Star Burners. This tool is very expensive and I'm not sure if it's worth to buy it.

- The spanner wrench Part number: AP2837957

Rather than order the tool, just use a crescent wrench or needle nose vice grips. Spread them far enough to get in the gaps , push down keeping positive pressure on the nut, and use a set of pliers to turn the nut. It works and if you are careful you will not ding the nut.

Also if your burners are not working it can be several items.

1. Bad electrode.
2. Bad spark switch.
3. Bad solenoid valve
4. Bad potentiometer
5. Bad simmer controller
6. Bad spark controller.

Check the first three before you start ordering kits or swapping controllers. I had am XLO burner not working and all the web advice pointed to the new simmer kit ($160 or so)

I pulled it apart, noticed the electrode had a lot of gunk, and as I had one replaced it before I started to put it back together to trouble shoot the spark switch and potentiometer.

Turned out that corrected the issue even though if I followed the Thermador trouble shooting guide it should not have.

Cost $5 (bought these a couple years ago), instead of $160.