Frigidaire Dishwasher Drain Pump Humming: Troubleshooting... | appliancefaults.com

Technical Background:

The dishwasher's Main Control Unit (MCU) initiates the drain cycle, sending 120V AC to the drain pump motor. The drain pump impeller rotates, forcing water through the drain hose to the house drain. If the impeller is blocked or the motor is faulty, the pump will hum but not pump water. The MCU also monitors the drain pump current. If the current is low or high, it may trigger an error code (though not always).

Symptoms:

The homeowner observes that the Frigidaire dishwasher runs through its wash cycle but doesn't drain the water at the end. The drain pump emits a humming sound, but no water is being expelled. There might be standing water in the bottom of the dishwasher.

Possible Causes:

Obstruction in the drain pump impeller
Debris lodged in the drain hose
Faulty drain pump motor
Clogged air gap (if applicable)
Defective drain check valve
Control board malfunction (rare)

Solution:

1

Disconnect power to the dishwasher at the breaker panel.
2

Locate the drain pump, typically at the bottom of the dishwasher. Access may require removing the lower access panel.
3

Inspect the drain pump for any visible obstructions. Remove the lower spray arm and filter assembly to access the sump area. Manually rotate the pump impeller to check for free movement.
4

Remove the drain hose from the drain pump. Check for kinks or clogs. Use a wet/dry vacuum to clear any obstructions from the drain hose.
5

Using a multimeter, test the drain pump motor for continuity. A reading of OL indicates an open circuit and a faulty pump. The resistance should be within a range specific to the motor (consult service manual).
6

If the motor has continuity, check the voltage at the drain pump connector during the drain cycle. You should see 120V AC. Use a multimeter and carefully probe the connector. Ensure the dishwasher is in a drain cycle when checking voltage.
7

If voltage is present and the pump is humming, replace the drain pump assembly. Ensure the new pump is properly seated and connected.

Safety Warning:

Always disconnect power to the dishwasher at the breaker panel before performing any repairs. This appliance operates on 120V AC, which can cause serious injury or death. Follow Lock Out/Tag Out (LOTO) procedures to ensure the circuit remains de-energized during repairs.

Prevention:

Regularly clean the dishwasher filter and sump area to prevent debris buildup. Avoid putting large food particles into the dishwasher. Periodically check the drain hose for kinks or clogs. Use a dishwasher cleaner monthly.

Expert Tip:

Many Frigidaire dishwashers have a service mode. To enter service mode, press and hold the Start/Cancel button for 5 seconds, then press Select Cycle three times within 6 seconds. This can often force the drain pump to run, even if there's no standing water, which helps with diagnosis.

Frequently Asked Questions

•How do I access the drain pump on my Frigidaire dishwasher?

Typically, you'll need to remove the lower access panel on the front of the dishwasher. Then, you'll likely need to remove the lower spray arm and filter assembly inside the dishwasher to access the sump area where the drain pump is located. Some models may require tilting the dishwasher back slightly.

•What resistance reading should I expect on a good Frigidaire dishwasher drain pump motor?

While the exact resistance value can vary, a typical reading for a good drain pump motor will be between 20 and 120 ohms. An open circuit (OL) indicates a faulty motor.

•If the drain pump is getting 120V AC but still just hums, is it definitely a bad pump?

Yes, if the drain pump receives the correct voltage (120V AC) during the drain cycle and only hums without pumping water, it is highly likely that the drain pump itself is faulty and needs to be replaced. The motor is likely seized or has an internal short.

Frigidaire Dishwasher Drain Pump Humming: Troubleshooting Guide

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•How do I access the drain pump on my Frigidaire dishwasher?

•What resistance reading should I expect on a good Frigidaire dishwasher drain pump motor?

•If the drain pump is getting 120V AC but still just hums, is it definitely a bad pump?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip: