I would say duff selector if other selections work 😉
The reason I say that is that the other components common to the grill are also common to the other cooking options therefore they would be faulty also 😕
John , as highlighted by a couple of others , although the selector switch may look fine , it could still be faulty . I’ve had a couple , not neccassarily on this particular model , that have shown no outward signs of damage/charring but have proven faulty.