Direct answer: When one LG cooktop burner stops heating, the usual cause is a simple mismatch in the burner setup, a burner cap or element not seated right, or a failed burner-specific part rather than the whole cooktop.
Most likely: Start by figuring out whether you have a gas burner that will not light or an electric burner that stays cold. On gas units, the burner cap and ignition path are the first checks. On electric units, a bad surface element or burner switch is more common.
Look at what the burner actually does. If you hear clicking but get no flame, stay on the gas-burner path. If the burner turns on but never gets hot, stay on the electric-burner path. Reality check: one dead burner usually points to a local burner problem, not a whole-appliance failure. Common wrong move: swapping parts before checking whether the burner is seated, assembled, and getting power.
Don’t start with: Do not start by ordering a control board or taking the cooktop apart. Most no-heat calls get narrowed down from the top side first.
You hear steady clicking and may smell a little gas, but the burner never lights or lights only after several tries.
Start here: Start with burner cap alignment, clogged burner ports, and whether the igniter is sparking in the right spot.
The indicator light may come on, but the burner itself never warms up.
Start here: Start with the correct burner setting, burner seating if it is a coil style, then compare that burner with another to narrow it to the surface element or burner switch.
The burner may warm for a minute, then drop out, or only work on some settings.
Start here: Look for a loose burner connection, a failing surface element, or a burner switch that is not sending steady power.
Nothing heats, or the cooktop looks powered but no burner works normally.
Start here: Check for a tripped breaker, lost leg of power on an electric cooktop, or a gas supply issue before chasing individual burner parts.
This is common after cleaning or after a pot boilover. A gas burner may click without lighting, and an electric coil-style burner may stay cold if the connection is not fully engaged.
Quick check: With the cooktop off and cool, lift and reseat the burner cap or the removable surface element so it sits flat and square.
On gas burners, clogged ports keep flame from spreading to the igniter. On electric cooktops, heavy spill residue around the connection area can hide heat damage or poor contact.
Quick check: Clean loose debris with a dry cloth or soft brush, then wipe with warm water and mild soap once the area is cool.
If one burner stays dead while the others work, the failed part is often local to that burner: a cooktop surface element on electric models, a cooktop igniter on gas models, or a cooktop burner switch on electric models.
Quick check: Swap only what is safely swappable from the top side, such as a removable electric surface element, to see whether the problem follows the part.
If all burners are affected, the issue is usually upstream. Electric cooktops can lose one leg of power and act half-dead. Gas cooktops can click normally but never light if gas is off.
Quick check: Check the breaker first on electric units, and confirm other gas appliances are working before assuming multiple burner parts failed at once.
These two failures look similar from the kitchen, but the checks are different and you can waste time fast if you mix them together.
Next move: If you can clearly sort the symptom, the next checks get much more accurate. If you cannot tell what type of failure you have, stop before disassembly and use the model tag to confirm whether the cooktop is gas or electric.
What to conclude: One burner acting up usually means a burner-level issue. All burners acting up points to supply, controls, or a broader cooktop problem.
A surprising number of no-heat complaints come from parts that were cleaned, bumped, or reassembled slightly wrong.
Next move: If the burner heats or lights normally after reseating and cleaning, you likely had a setup or debris problem, not a failed part. If the burner still will not heat, move to a comparison test with another burner.
What to conclude: A burner that comes back after reseating was not making proper contact or was not directing flame correctly.
A side-by-side check helps you tell whether the failure follows the burner part or stays with the cooktop position.
Next move: If the failure follows the burner part, you have a strong part-level diagnosis and can replace that burner component with confidence. If the failure stays at the same burner location, keep going and check the control side and visible signs of heat damage.
Once setup and easy swaps are ruled out, the next likely failures are the burner-specific control on electric models or the ignition part on gas models.
Next move: If the clues line up cleanly with one branch, you can move ahead without shotgun parts buying. If the symptoms are mixed, intermittent, or affect multiple burners in different ways, stop at the top-side diagnosis and plan for a pro or a model-specific service procedure.
By this point you should have enough evidence to replace one burner-level part with a good chance of success, or to stop before the repair gets into live wiring or gas components.
A good result: Test the burner through low, medium, and high settings and make sure it heats or lights consistently several times in a row.
If not: If the new part does not fix it, stop replacing parts and have the cooktop diagnosed for wiring, harness, or control issues.
What to conclude: A confirmed top-side diagnosis supports a burner-level repair. A failed repair outcome usually means the fault is deeper than the first replaceable part.
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That usually means the problem is local to that burner. On gas models, think burner cap alignment, clogged ports, or a bad cooktop igniter. On electric models, think a bad cooktop surface element or cooktop burner switch before you suspect the whole appliance.
Usually a breaker issue affects more than one burner or the whole cooktop, especially if one leg of power is lost. If only one burner is dead and the others are normal, the fault is more likely at that burner.
Most often the cooktop burner cap is off-center, the burner ports are clogged, or the spark is not reaching the gas stream correctly. Clean and reseat the burner parts first. If one burner still has weak or no spark while others work, the cooktop igniter becomes more likely.
If your cooktop uses removable elements and the no-heat problem follows that element when swapped with a matching working burner, the element is the bad part. If the problem stays at the same burner position, look harder at the cooktop burner switch or connection.
Replace the burner part first only when your testing points there, such as a failed swap test on a removable electric element. If a known-good burner still stays dead at the same position, the cooktop burner switch is the stronger bet.
Not for long. Intermittent heating can mean a loose connection or failing switch, and those can overheat. If you notice burning smell, discoloration, or a loose-feeling control, stop using that burner until it is repaired.