Sounds like the spark module to me. The spark switch is ok, since other igniters do work when you turn on the right front burner knob. The igniter is also ok, you've checked that. You can also check the wire that goes from the spark module to the right front burner igniter to make sure both ends are plugged in and the wire has no breaks in it, but I'm pretty sure you're looking at replacing the spark module.
- Replacement
spark module for your model.
When replacing the spark module, unplug the power to the cooktop and make sure to note which wire goes where first. The spark module is located in the right front corner, between the control panel and the right front burner. You may have to remove the top glass if you cannot access the module by removing the right front drip pan and burner. Not a complicated job, maybe a little time consuming if the top has to be removed (be careful with the glass).