If cycle proceed normally after waiting for a while, then the control is probably OK. It stands by a while because it does not read correct temperature before proceeding.
If the appliance is connected to both hot and cold water, open more the hot water faucet.
If the water is not heating at all, check heating element for continuity, using a tester.
If water is heating regularly, but cycle is still slow, check thermic sensor.
Here are more suggestions from Repairclinic:
The cycles times are too long
If your dishwasher's cycle times are too long, check these:Water pre-heatingCycle not completing
dishwasher may pre-heat the water. If so, and if the water entering the
dishwasher is cool, the heater may take up to half an hour to heat the
To avoid the wait, increase the incoming water
temperature before turning on the dishwasher. Do that by running the
kitchen sink faucet until the water runs hot. Or increase the
temperature of the hot water to the entire house at the hot water
Warning! To lessen the risk of scalding, don't set the hot water heater temperature higher than 120 degrees Fahrenheit.
If you need replacement parts or exploded views you find them here.