Whirlpool's cited guidance says a flashing Sani light means the required sanitizing temperature was not achieved. A finished wash therefore does not establish a successful sanitize result. Check the exact model's instructions, incoming-water requirements and any cycle interruption. Preserve the indication and arrange the appropriate appliance or plumbing assessment rather than treating a reset as proof.
Read the actual cycle result
A wash can finish while its sanitizing option has failed. Identify the dishwasher model, selected cycle and exact light or display message. A Sanitize result is a different observation from a machine that never filled or still holds wastewater.
Whirlpool's Sanitize-light guidance says the Sani LED flashes when the dishwasher detects that its temperature requirements for sanitization were not met. It calls this an indication that the dishes were not sanitized. Apply that meaning to equipment covered by the matching guidance, not every brand's flashing lamp.
Keep the failed result with the cycle history. A cleared display, completed drain or control reset does not establish that the temperature requirements were achieved on that load. Use the owner's instructions for the next appropriate action instead of assuming the dishes achieved a sanitizing result.
Separate water delivery from a hot-cycle interruption
Whirlpool's article asks about water temperature and refers to the minimum stated in the Owner's Manual. Compare the installed dishwasher's actual supply requirements and recent changes with the responsible provider. Do not raise a home's water-heater setting solely because this indicator flashes; delivered-water requirements and household scald protection need appropriate review.
The same article identifies opening the door during the cycle as a possible reason heat escaped. Record any door opening or power interruption you already noticed. That history helps assessment but does not prove a heater, inlet valve or control has failed.
Preserve the hot-cycle precautions
Whirlpool's adding-items guide says not to add items during high-temperature portions such as Sanitize, Hi-Temp Wash or Dry. It also says pause and resume features differ by model and directs readers to the matching Use and Care Guide.
Do not open a hot cycle just to test the explanation, reach into spraying equipment or bypass a door interlock. Follow the model's ordinary operating precautions. This status-light check is not an energized heater or electrical-control repair procedure.
Choose the service task from the actual symptom
No filling after installation and water left after draining require separate investigations. Neither problem should be inferred from a failed Sani result alone.
Keep the model, exact indication, cycle selection and interruption history ready for manufacturer or appliance service. A deficient household supply connection belongs with the appropriate plumbing provider; dishwasher water-line installation describes that separate connection. Stop use and obtain suitable help for leakage, burning smells or another hazard rather than repeatedly running cycles to force a successful light.