WD21X10519 High-Precision Dishwasher Flood Switch & Thermistor

Key Features

• Dual-Function Sensing: Combines a high-sensitivity water level flood switch with an integrated thermistor, allowing the control board to simultaneously monitor water levels and temperature for optimal cycle performance.
• Critical Overflow Protection: Engineered as a primary safety device that detects "overfill" conditions, signaling the drain pump to activate and preventing potential kitchen flooding.
• High-Accuracy Temperature Monitoring: Features a built-in thermistor that provides real-time heat data to the control board, ensuring "Sanitize" and "High-Temp" cycles reach the required thermal targets.
• Moisture-Sealed Connector: Includes a specialized multi-pin connector housing designed to resist corrosion and electrical shorting in the high-humidity environment beneath the dishwasher tub.

Replaces / Cross-Reference Part Numbers

• Primary Part: WD21X10519.
• Legacy Cross-Reference: WD21X10492, WD21X20204, 3028650.
• Industry Standards: AP5781639, PS8690623, EAP8690623.
• Other: AH8690623, B00MOCKVWC, PD00007065.

Compatibility & Fitment

This flood switch is the standard replacement for most GE-manufactured Stainless Steel Tub and modern plastic tub dishwashers produced after 2014. Key compatible series include:

• GE & GE Profile: Fits hundreds of ADT, CDT, DDT, GDF, GDT, and GDW series models (e.g., GDT695SSJ2SS, GDT580SSF0SS).
• GE Café & Monogram: Compatible with various CDT and ZDT high-end units (e.g., CDT725SSF0SS, ZDT870SSF0SS).
• Hotpoint & Haier: Fits many HDF and QDT series models utilizing the WD21X10519 switch style.
• Note: This switch is typically located in the Front-Center of the Sump, beneath the lower spray arm and filter.

When to Replace

• "88" or "H2O" Error Codes: The dishwasher displays a water supply or leak error on the front panel and refuses to start a cycle.
• Dishwasher Won't Fill: The unit starts the drain pump but never opens the water inlet valve because the switch falsely senses an "overfill" condition.
• Water Won't Heat: The dishwasher runs through the cycle but the water stays cold, indicating the internal thermistor has failed and isn't reporting temperature to the board.
• Constant Draining: The drain pump runs continuously even when the tub is empty, often caused by a "stuck" float switch inside the WD21X10519 housing.
• Beeping During Cycle: The dishwasher stops mid-cycle and beeps, signaling a sensing error or a perceived flood risk.

Installation Tips

• Safety First: You MUST unplug the dishwasher or turn off the circuit breaker. This repair involves working with sensitive electrical sensors near the water sump.
• Access the Sump: Remove the lower dish rack and the fine-mesh filter. The flood switch is usually accessible from the inside of the tub, though on some models, you may need to remove the lower kickplate to reach the wiring.
• Check for Debris: Before replacing the switch, check the area around it for seeds, toothpicks, or film build-up. Sometimes debris can physically jam the float, causing it to send a "flood" signal even when the switch is good.
• Dry the Connector: Ensure the wire harness connector is completely dry before plugging it into the new switch. If water has leaked into the plug, use a hair dryer (on cool) to dry it out to prevent immediate sensor errors.
• The "Quarter-Turn" Install: Most GE flood switches twist into place. Ensure the rubber gasket is seated properly before locking it down to prevent a slow leak into the base pan.