If your cooktop is not heating, the issue may be due to a faulty heating element, a damaged burner, a broken control switch, or an issue with the power supply. For electric cooktops, the heating element may need replacement. For gas cooktops, a clogged burner or malfunctioning igniter could be the problem. If you experience uneven or no heating at all, it’s best to schedule a professional cooktop repair service for diagnosis and repair.