Robin P Miami , FL July 10, 2014 Appliance: Thermador Steel Burner Gas Cooktops SGCS304RS Thermador Cooktop Sgcs304rs: Thermador cook top sparking but not lighting. How to replace Potentiometer Kit. Replaced potentiometers and a control with bosch-potentiometer-kit-497235. 3 People found this story helpful Do-It-Yourself Rating: Repair Time Estimate: 30-60 minutes