The short answer: if a Thermador Star burner clicks but never lights, the spark is firing but gas is either not reaching it or not catching. The usual culprits are debris packed into the star-shaped ports, a burner cap that is wet or seated off center, or a worn spark electrode. Dry the burner, clear the ports, and reseat the cap. If it still will not light, or if the clicking spreads to every burner, the electrode or the igniter module needs service.
What Is Happening at the Burner
Thermador's patented Star burner uses a star-shaped port pattern instead of the usual ring, which spreads the flame wider for more even heat. That same shape has a quirk: the points of the star are little pockets where boil-overs, grease, and food debris collect and choke off the gas. When you turn the knob, the spark electrode clicks to light the burner. If the ports are blocked or the cap is off, the spark keeps firing into gas that is not there, and you get the endless click with no flame.
Because the Star burner is a mechanical gas system, there are no numeric fault codes here. The diagnosis is symptom based, reading the clicking, the flame pattern, and whether one burner or all of them are affected, rather than a code on a display.

Symptoms and What They Point To
| Symptom | Likely Cause | Owner or Tech |
|---|---|---|
| One burner clicks, no flame | Clogged star ports, wet or misaligned cap | Owner can clean first |
| One burner clicks, still nothing after cleaning | Worn or cracked spark electrode firing weakly | Technician |
| All burners click together | Wet cooktop, or a failing spark igniter module | Owner dries first, then tech |
| Weak or uneven star flame | Carbon buildup in the star points or a dirty orifice | Owner cleans, tech if it persists |
| Knob turns, no click at all | Failed electrode connection or igniter module | Technician |
The pattern tells you a lot. One burner acting up points at that burner's cap, ports, or electrode. Every burner clicking at once points at something shared, usually moisture on the cooktop or the spark module that fires them all. For a broader look at this across brands, see our page on a burner that is not igniting.
Clean the Ports and Reseat the Cap First
Let the burner cool and dry completely, since even a little moisture from a boil-over or a recent cleaning will make the igniter click without lighting. Lift off the cap and use a straightened pin or a thin brush to clear each point of the star, then clear the small igniter opening. Set the cap back down squarely, fully seated with no gap. This one routine, done properly, resolves a large share of Star burner ignition complaints, and doing it regularly keeps the flame full and even.
The Electrode and Igniter Module
If the ports are clean and the cap is seated but the burner still will not catch, look at the spark. A cracked ceramic electrode or a greasy electrode tip sparks weakly and misses the gas. If a single burner has a good click but no light, the electrode is the suspect. If every burner clicks nonstop on a dry cooktop, or a knob produces no click at all, the spark igniter module that drives them is usually failing. Both are model-specific repairs rather than owner fixes.
Thermador's ExtraLow simmer setting cycles the flame very low, so on the lowest settings the burner may look nearly off or appear to flicker. That is normal simmer behavior, not a failure. Before you chase an ignition problem, make sure the knob is turned to a normal light or high position first, and confirm the flame simply will not establish at all rather than sitting at a designed low simmer.
What a Technician Checks
A proper Star burner diagnosis follows the gas and the spark. The technician confirms gas supply to the cooktop, inspects the star ports and cap for blockage and correct seating, and checks the spark electrode for cracks, carbon, and a strong consistent spark. If one burner is at fault, the electrode and its wiring are tested. If all burners click, the spark igniter module and the cooktop for trapped moisture are checked. A weak or uneven flame that survives cleaning sends the tech to the burner orifice and gas pressure.
When to Call a Technician
Clean the ports, dry the burner, and reseat the cap yourself. Call for service when a single burner still will not light after cleaning, when every burner clicks on a dry cooktop, when a knob produces no click at all, or when the flame stays weak or uneven. Electrode and igniter module work involves the gas system and live spark circuits and needs proper testing. Every repair we perform in Brookville carries our Written warranty terms for eligible completed repairs. Diagnostic and travel fees, if applicable, are confirmed before the appointment and before repair approval.
Frequently Asked Questions
Why Does My Thermador Star Burner Click but Not Light?
Why Are All My Thermador Burners Clicking at Once?
Why Is My Thermador Star Burner Flame Weak or Uneven?
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