Excessive foaming when using Rinse Only Cycle in

Excessive foaming when using Rinse Only Cycle in Kitchenaid Dishwasher. I've had this dishwasher only 3 weeks. There is no detergent in the dispenser. Rinse Cycle should be only water; no soap. Rinse Aid should not be dispensing either. What could be the problem? Normal wash cycle leaves residue on glassware. That is why I run the Rinse Only Cycle. I have done this over and over with the same results? HELP!!!