Dishwasher fills with water but does not wash; you hear filling and maybe a hum, but spray arms do not rotate.

Safety first: Disconnect power and water.

• Check for obstructions: Remove spray arms and filters. Inspect the sump for debris that could jam the pump.
• Access circulation pump: Lay the dishwasher on its back and remove the bottom panel. Locate the circulation pump and attempt to turn the impeller by hand.
• Inspect capacitor: If fitted, test the pump's start capacitor with a capacitance meter and replace if out of spec.
• Electrical test: Measure motor winding resistance. An open or shorted winding indicates a failed pump.

Replace the circulation pump assembly if seized or electrically faulty.