Hi, my name is Peter.
The burner has a sensor that tells the hot surface light to come on and also regulates the burner, so a sensor on one of the burners is stuck on. Since the small/lar\ge burner stopped working at the same time that burner probably has a defective sensor. You can only get the sensor when you purchase the burner.
You may send additional questions directly to me.
Please push the green accept button.
Are you saying that the burner is faulty and must be replaced?
You should verify that the burner is defective by testing the sensor with an ohm meter, but by the symptoms you have provided I would test the burner first.