Take out the little white pump at the bottom. It should have a label on the back that says 12 volt .30ma. You might have to cut the wiring to test it with an external 12 volt source and a 5 ohm resistor. Splice or cut the wire and test it to see if it is faulty. This might be why youre add water light is on after you put water in it and the light wont go off.
