Replacing broken double-burner element in Bosch cooktop

Question

I've got a Bosch cooktop (part number PKF645E01A) and the inner-ring of the double-burner element has stopped working (the outer ring works fine). I've opened up the cooktop and notice that the double-burner element has 3 wires.

I've checked the resistance between the wires and have found the following:

• The first and second wires have zero resistance:

  

• The first and third wires have 33.3 ohms of resistance:

  

• The second and third wires have zero resistance:

  

It seems that the element is faulty, but before I go ahead and order a replacement burner, I'd like to confirm that this is in fact the case, which brings me to the following questions:

1. Based on the resistance values posted above, does it seem as though this burner is defective? If there's not enough information to know this, what else can I check?
2. Is there a way I can connect this burner directly to a power source to test the burner elements so I can either confirm that the inner element is faulty, or demonstrate that it works?
3. What's the purpose of the three wires?

Thanks!

Update 2023-12-30T00:53:27.168Z:

Thanks for all the fantastic responses! I followed the advice from ecnerwal and ordered a replacement double-burner element from here for €50 (plus €75 for shipping!) and after swapping out the old burner with the new one, here are the new meter readings:

• The first and second wires have 100Ω of resistance:

  

• The first and third wires have 34.7Ω of resistance:

  

• The second and third wires have 66Ω of resistance:

  

And I'm happy to report that the new burner functions as expected:

• Before

  The inner ring doesn't work:

  

• After

  Both rings work:

  

Answer 1

A 2-element burner with 3 contacts is normal and expected. One contact is common to both elements, the others are the opposite ends of the two elements. Could be done with 4 contacts, but if the manufacturer can save 0.50 € by using one less contact, you can be sure they will.

Your actual resistance readings are infinite, 33.3Ω and infinite. 0.L on the Mega-Ohms scale is an open circuit. So your burner looks like this, electrically (ignoring the burner controls between the line and the elements):

{2}--- ---{1}---33.3Ω---{3} ...| Inner ring | Outer ring | ..L1 <-240V-> L2 <-240V-> L1

The element between 1 & 2 is broken, thus an open circuit, thus infinite resistance between 1 & 2 and 2 & 3

While you could hook it up to power, there's no need and some hazard from making jury-rigged connections. The infinite resistance reading on the 1-2 element is a sure sign that it's broken. And it's been hooked up to power in your stove and not worked. I suppose if you hooked up a 12V supply (car battery charger, say) capable of 360 or more mA you might feel the warming from a whopping 4.3 Watts on the outer ring, and nothing on the inner ring, without getting into hazardous voltages. Or you could use your meter in current (Amperes) mode to see the current, and lack of current. Just pay attention the fact that current is done with the meter in series with the load, not in parallel like voltage measurements.