Dishwasher top rack not cleaning well; lower rack is clean but upper items remain dirty.

Safety First: Turn off power before removing internal parts.

Inspect upper spray arm:

• Remove the upper spray arm and clean all jets thoroughly.
• Ensure the arm spins freely when reinstalled.

Check feed tube:

• Inspect the vertical feed tube at the back of the tub for cracks or disconnections.
• Ensure the upper rack manifold properly engages the feed tube when the rack is pushed in.

If still poor:

• The diverter or circulation pump may be at fault and require further diagnosis.