If your dishes are not drying properly, you most likely have an empty rinse aid dispenser, defective heating element or the controls for the wash cycle are damaged. Diagnosis of a control failure is a bit more involved than can be summarized here. For the heating element, you can remove the element on a General Electric (GE) appliance, (or any other make and model) and replace it, by following these simple steps:
1) Collect and have available the following tools: flashlight or other light source, flat head screwdriver(s), Philips head screwdriver(s), torx head screwdriver(s), socket set (small size), dielectric grease, low strength Loctite.
2) Shut off the power to the dishwasher.
3) The heating element, typically located at the bottom of the washer, may have a cover. If so, remove the cover using the proper tool.
4) Find where the heating element terminals are, and you will see that wires connect the element. Label each wire, and then disconnect the wires from the element. Pull on the plug itself, not on the wires.
5) Replace the heating element with an identical make and model, if possible. If you are using Bosch dishwasher parts, for example, continue to use these when you replace the parts. You may have to unscrew locking screws or nuts and reinstall them when replacing the element. Use dielectric grease and Loctite if indicated. You will need to use the proper tools to do this, so again, make sure they are handy when you start the job.