Top rack of dishwasher does not clean at any location in rack while everything in the bottom does clean. Checked to sprayer and it appears to spin freely and not clogged. Water is supplied to top rack sprayer through a horizontal plastic pipe which seats on a port in the back of the dishwasher when the rack is pushed in. Suspect water is not getting to this top port. Is there a way to check this or can there be another problem?
