Roper Dishwasher Sanitize Light Not Working:... | appliancefaults.com

Technical Background:

The sanitize light is typically activated by the main control board (MCU) after the dishwasher has reached a sufficient temperature (usually around 150°F) during the final rinse cycle. The MCU monitors the temperature sensor (thermistor) and controls the heating element to maintain the proper temperature. If the MCU doesn't receive the correct temperature reading or fails to activate the heating element, the sanitize light will not illuminate.

Symptoms:

The homeowner observes that the sanitize light on their Roper dishwasher does not illuminate at the end of the wash cycle, even though the dishwasher appears to complete its cycle normally.

Possible Causes:

Faulty temperature sensor (thermistor).
Defective heating element.
Issues with the main control board (MCU).
Wiring harness problems or loose connections.
Insufficient water temperature.
Failed high-limit thermostat.

Solution:

1

Disconnect power to the dishwasher at the breaker panel (LOTO).
2

Check the thermistor resistance with a multimeter. It should read approximately 50k ohms at room temperature (70°F). Replace if out of range.
3

Inspect the heating element for continuity with a multimeter. If there is no continuity, replace the heating element.
4

Examine the wiring harness and connections to the heating element, thermistor, and main control board. Look for burnt or loose connections. Repair as needed.
5

Verify that the incoming water temperature is at least 120°F. Adjust the water heater if necessary.
6

Check the high-limit thermostat for continuity. If open, replace.
7

If all other components test good, the main control board (MCU) is likely faulty and needs replacement.

Safety Warning:

Always disconnect power to the dishwasher at the breaker panel before performing any repairs. Lock out/tag out (LOTO) procedures must be followed. High voltage is present within the dishwasher. Failure to disconnect power can result in serious injury or death.

Prevention:

• Run the dishwasher regularly to prevent mineral buildup.
• Use a dishwasher cleaner periodically to remove grease and food particles.
• Check and clean the spray arms and filter regularly.
• Ensure the water heater is set to at least 120°F.

Expert Tip:

Many Roper dishwashers have a service mode that can be accessed by pressing a specific sequence of buttons (check the tech sheet behind the kick panel). This mode often includes diagnostic tests that can help pinpoint the cause of the problem.

Frequently Asked Questions

•Where is the thermistor located in my Roper dishwasher?

The thermistor is typically located inside the wash chamber, often near the bottom or integrated into the heating element assembly.

•How do I know if my main control board is bad?

The main control board is usually the last component to be replaced after all other possibilities have been eliminated. Symptoms of a bad control board may include erratic behavior, failure to start, or failure to respond to button presses.

•What type of heating element does my Roper dishwasher use?

Roper dishwashers typically use a resistance-type heating element. The wattage can be found on the element itself, usually around 600-800W.

Roper Dishwasher Sanitize Light Not Working: Troubleshooting Guide

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•Where is the thermistor located in my Roper dishwasher?

•How do I know if my main control board is bad?

•What type of heating element does my Roper dishwasher use?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip: