WP35-6780 Drain Pump Assembly – What Part Fixes Dishwasher That Won't Drain
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Understanding the Problem
What the WP35-6780 is and why it matters: The WP35-6780 is a drain pump assembly used on many Whirlpool, KitchenAid, and Maytag dishwashers. It contains the pump motor and impeller that evacuates used wash water through the dishwasher drain hose. When this pump fails you’ll commonly see water left in the tub after a cycle, hear humming or grinding noises during drain, or trigger a drain-related error code. Step-by-step diagnostics and repair (practical): 1) Safety first: Unplug the dishwasher or turn off its circuit breaker and shut off water to the appliance before you start. Always work with power removed. 2) Confirm the symptom: Run a drain-only or quick cycle and listen closely. If the unit tries to drain but water stays, or you hear a humming/grinding sound from the lower front, the drain system is suspect. 3) Clear filters and sump area: Remove the lower rack, take out the filter assembly and inspect the sump for food debris, broken glass, or obstructions that can jam the impeller. 4) Check the drain hose and air gap: Inspect the drain hose for kinks or clogs and check the sink air gap (if present) for blockage. Remove the hose at the sink/garbage disposer and check for restrictions. 5) Listen for pump action: Start a drain cycle with the door open (safely) and listen. If the pump hums but no water moves, the impeller may be jammed or the pump is weak. 6) Electrical check at the pump: With power off, access the pump wiring and check for loose or burned connectors. Use a multimeter to test for continuity across the pump motor terminals. An open circuit usually means a failed motor. 7) Live bench test only if experienced: If you’re comfortable and know safe procedures, you can bench-test the removed pump by briefly applying the correct line voltage to verify motor rotation. If it does not spin or draws excessive current, replace it. 8) Replace the pump assembly: If cleaning and hose checks don’t fix it and the pump fails continuity or bench test, replace the WP35-6780 drain pump assembly (steps below). After replacement, reassemble, restore power, and run a drain cycle to confirm the repair. Basic replacement steps (high-level): 1. Turn off power at the breaker and shut off water supply. 2. Pull out the lower rack and remove the filter/sump cover. 3. Remove the toe kick/kick plate if needed to access bottom of machine. 4. Disconnect the drain hose and any clips, and position the dishwasher forward if necessary to access the pump from underneath. 5. Remove mounting screws/clips holding the pump and disconnect the electrical connector(s) and any hose clamps from the pump. 6. Remove the old WP35-6780 assembly and install the new pump in the same orientation, reconnect hoses and wiring, and secure mounting hardware. 7. Reinstall sump/filter, lower rack, and kick plate. Restore power and water, then run a test drain. Safety note: Always disconnect power before opening the dishwasher. If you’re not comfortable working with electrical testing or applying live voltage for bench tests, replace the pump or call a qualified appliance technician.
Common Symptoms
Dishwasher does not drain or leaves water after cycle; humming or grinding noises during drain; drain-related error codes; occasional leaks from the pump area.
Common Causes
- Clogged sump, filter, drain hose, or air gap
- Impeller jammed by debris (glass, food, small utensil parts)
- Pump motor failure (open winding, worn brushes or internal mechanical failure)
Popular Parts That Fix This Problem
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Helpful Repair Tip
Before replacing the pump, remove filter/sump debris and disconnect the drain hose — sometimes a clog or lodged object (glass/utensil tip) is the only problem. If the pump hums but won’t turn, the impeller is likely jammed or the motor has failed and the WP35-6780 needs replacement.
Frequently Asked Questions
Can I run the dishwasher with the pump removed or bypassed?
No — running the dishwasher with the pump removed or bypassed can cause flooding, leaking, or damage to other components. If the pump is faulty, replace it before running cycles. For short tests, remove standing water and run a short drain-only cycle after installing a replacement or performing a proper temporary repair advised by a technician.
How long does a drain pump like the WP35-6780 typically last?
Drain pumps often last many years (5–10+), but life depends on use and whether debris repeatedly gets into the sump. Regularly cleaning the filter and avoiding putting small hard objects into the dishwasher will extend pump life. If the pump becomes noisy, hums, or fails continuity checks, it's time to replace it.
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