Why does the sanitizing light not go on?

Per the owners manual: Your Bosch dishwasher is NSF Certified. The wash cycles that are NSF Certified are Power Scrub Plus, Scrub Wash, Regular Wash, and Delicate/Economy Wash (see the Model Features Chart on page 6 of this manual). When these cycles are complete, the "Sanitized" light on your dishwasher control panel will illuminate. ''However, if your household water supply is too hot, your dishwasher's heating time may be reduced, and the light may not illuminate.