A dishwasher has an internal heating element that dries your dishes after the washing cycle is done. This element is located on the bottom of the tub. If your dishes aren't drying properly, troubleshoot the issue before contacting a service technician. Repair fees are often expensive, and you can save money by doing the work yourself.
If your dishes aren't dry after the cycle is done, use a rinse aid to assist the drying process. Rinse aids reduce the amount of moisture in the tub. Check the rinse aid dispenser and add more if it's empty. Use a heated dry setting. Air dry settings do not actually dry your dishes. Always unload the bottom rack, first. Water trapped in cups on the top rack can fall onto dishes on the bottom rack. Plastic and Teflon-coated dishes normally don't completely dry. Don't overload the dishwasher as this can prevent air from freely circulating around your dishes.
Your dishwasher won't dry your dishes properly if the heating element is defective or burned out. Disconnect the dishwasher from the power source, and visually inspect the heating element. See if it has any burned out or broken areas. You must replace the heating element if it's defective since you usually can't fix this element. If the element looks fine, remove the panel underneath the door and take out the heating element. Look at the terminals and connectors and clean or replace these components if corroded. Check the terminals for power, and if so, get a new heating element.
The thermostat regulates both the drying cycle and water temperature. Test the thermostat by selecting the shortest wash cycle at the highest temperature setting possible. Open up the dishwasher and see if the interior is warm during the drying cycle. If not, the thermostat is defective. You usually can't fix this component. Order replacement parts from a dishwasher parts dealer.
The drying fan circulates warm air around the dishwasher in some high-priced models. The drying fan often makes a squealing or groaning noise when it's turning on. Unplug the dishwasher from the outlet and remove the main access panel. Examine the drying fan and see if debris is preventing it from moving freely. Clean it. See if any of the fan blades are rusted out. Try cleaning the blades. If the fan isn't moving at all, it's probably burned out, and you need a new one.