Diagnosis
The sanitize indicator requires the final rinse water to reach 150°F and maintain it for a specific time. Failure indicates insufficient hot water supply.
How to Fix It
Ensure your household water heater is set to at least 120°F. Run the hot water at the sink next to the dishwasher until it is fully hot before starting a cycle. Use a cycle with a sanitize option (Heavy, Normal, Auto) and ensure the sanitize button is selected.
If That Didn't Work
The internal heating element or its thermostat may be faulty, preventing the unit from achieving the required final rinse temperature.
Heads Up
The sanitize light is an indicator, not a washer setting. The cycle will run without it, but the NSF certification requires that temperature to be met for the light to illuminate.