The vent might not be opening properly. As the dishes are drying, many dishwashers use a vent to let out the hot, steamy air generated during the rinse cycle. If the vent does not open properly, the dishwasher will leave moisture on the dishes. Check the vent to ensure that it is opening properly.
Vent Fan Motor
Some dishwashers use a vent fan motor to help dry the dishes at the end of the cycle. If the fan motor is not working, the dishwasher won’t dry the dishes properly. To determine if the fan motor has failed, test the motor for continuity. Also, try turning the fan blade by hand to ensure that it spins freely. If the fan motor has burned out or the fan blade won’t turn smoothly, replace the vent fan motor.
For Bosch Dishwasher Ascenta models, open the door to reset it. Hold the Start-Reset button for about 5 seconds or until the Active indicator turns off. Shut the door of the dishwasher to allow it to thoroughly drain before turning it off. When the dishwasher completes draining, it beeps to indicate that it is done.
For models that have a clock display, hold the combination Start-Resetbutton until the clock display changes to 0:00. Close the door of these models and wait until the clock reads 0:01 before pressing the On-Offbutton.
Check out the dishwasher not drying page for some additional fixes and explanations.