Identify the zone
Use front-left or another clear position, and say whether a setting number appears. A display response does not confirm that power reaches the heating arrangement.
Match the technology
Induction and radiant hobs work differently. Give the model and any cookware change. Assessment can distinguish control, supply and zone-specific issues without presuming a replacement ring is required.
A useful distinction
On a multi-part zone, the inner area and an optional outer section may be selected differently. State which area fails and which setting is shown, using only results already known from ordinary cooking.