Dishwasher will not drain

Dishwasher failed to drain after rinse cycle. Checked for blockages - none. Restarted cycle - tub filled but did not drain. checked and the pump appeared to be powered - vibration and a humming or buzzing noise but again did not pump out. Any other checks before I replace the pump?

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Replacement parts for GSD5500G022B models | AppliancePartsPros.com

Remove the kick plate.
Start a drain you can see the end of the motor with it’s cooling fins.
Is the motor running?
Does it try to start?
If it tries to start but does not.
Open the door slightly or better yet unplug the unit and try to rotate the motor’s armature with a small screwdriver. If it will not turn, remove sump cover from inside the tub and check that it is clean and that there is nothing wrapped around the chopper. Becareful often there is glass in the sump.

If the unit runs OK on wash then odds are high that the motor etc. is OK.

Check that the drain solenoid, left hand side of the pump module is being pulled down for draining.

I have checked the solenoid - it is clear and shows normally closed circuitg opens when float is raised. Pump motor is in the back right of the unit. Have removed covers and moved dishwasher out to access the pump. Cannot see the rotor or the ?chopper?

[quote=denman;149852] remove sump cover from[COLOR=red]inside the tub[/COLOR] and check that it is clean and that there is nothing wrapped around the chopper. Becareful often there is glass in the sump.

chopper/impeller is accessed from inside the tub.