If the ignitor is sparking then it's probably the gas flow near the ignitor. Clean the holes in the burner ring particularly the ones near the ignitor. Also clean the ignitor carefully with a Q-tip and rubbing alcohol.

Hello, just to clarify: the burner gets gas just fine but doesn't click when I turn the knob (I regularly use the burner after I start it with a match). If I turn the knob to another burner then the burner in question not only clicks, but I see the spark coming out of the igniter too.

The 1 knob to the specific burner doesn't seem to be connected to the igniter or something.

Any ideas?

Sorry, can't help with that. Maybe someone else on this forum can. You might need a service call or else live with lighting the burner manually.

I am not sure I understand your description of the problem.

So, let me suggest another quick test. Pushing in on the knob of one burner will make all of the ignitors fire, right? So, if you turn two knobs at the same time --- and by that I mean pressing and turning both the problem burner's knob and another one, so the ignitors are sparking --- will the problem burner light as the other one does?

If the problem burner does not light even though it's ignitor is sparking, then something is gummed up in the burner and things need to be cleaned as suggested above. (Also helps to get some fine, stiff wire and ream the holes. Stripping the paper/plastic off a wireties can be a good improvised tool for this.)

If the the problem burner's ignitor is not sparking, then you have a bad ignitor, which is a pretty simple fix.

If the problem burner's ignitor sparks when you are igniting other burners but does not spark from when pressing turning its knob, then the problem is most likely with the switch/connection where the know shaft goes into the valve mecahnism at the front of the stove. (It is also possible that your stove's ignitor module has started to fail, but, with these kind of symptoms, it is more likely that the problem is at the valve.) I suggest you get your stove's model number, go to SearsPartsDirect.com and look at the parts diagrams for the burner controls. This should help you figure out if you could maybe to get things apart to apply some contact cleaner or simply replace the value unit (it might not be something you can disassemble.)

Or, do the above tests, call a repair service and tell them what you've found. They can probably fix it about 10 minutes.

Correct: if I push in the knob of another burner the igniter for both the igniter that I'm starting AND the faulty burner work just fine (I can then turn the knob of the faulty burner and it lights perfectly).

So yes, the igniter sparks when igniting other burners.

Could it be just that a wire is loose by the knob?

You will probably find this Youtube item and others close to it on the web page helpful.
Your system may differ slightly or be a bit more modern. Perhaps it has auto relight.

In any case, good luck!

Here is a link that might be useful: Ignition problem

I have the same problems only with the right front one. I am not impressed with it and wish I would have stuck with Bosch.