The solid hotplate element is actually made up of a number of elements all combined into 1 assembly. For clarity, lets call these internal elements "Circuits"
The selector switch setting defines which "circuits" on the solid plate are in use.
Setting 1 will use 1 circuit, so it doesnt get very hot
Setting 2 will use 2 circuits etc etc. (Not quite as simple as that, but you get the idea)
It is extremely rare for a selector switch to cause this issue. To do so, it would mean some of the contacts on the selector have burnt out It is very likely that the solid hotplate has some of its "circuits" open circuit
It is unusual for solid hotplates to use regulators, these are generally used for ceramic rings. Even if yours does use regulators, it will still be the hotplate element.
this is a very common fault on these elements.
Once you have replaced it, start oiling them very lightly with a thin oil. The solid hotplate elements are made up of porous cast iron, when water seeps into them, they rust internally which eventually leads to them blowing fuses. Oiling them in this way, once a week for a month or so when they are cold, helps to waterproof them and gives them longer life. Check the handbook, it will advise to do this.