Whirpool Quiet Partner III doesn't completely dry dishes

Dishwasher does not completely dry dishes. Top rack drys ok, but bottom rack will have moisture film. There will be a small amount of water in the bottom of the tub at the end of the cycle. Hot steamy air comes out of the unit if door is opened during drying cycle.

Heater element and rinse aid seem ok visually. There are no signs of distress or damage to either part.We do not use a rinse aid solution because we have soft water and top rack dishes and glasses are spotless.

No debris accumulation in bottom of tub. Drain hose and garbage disposal are ok. Drain hose is clear and loops up from dishwasher and back down to the disposal drain inlet. All panel LEDS seem to work appropriately.

Any ideas?

Thanks - Rick