Dishwasher Not Working at All (no sounds, nothing)
Fuses - The first thing you want to check when you have this problem is the power getting to the dishwasher from the house. Turn the breaker off then back on and see if the power is restored to the machine. If that does not work test the fuse in the box to make sure it is not blown.
Wiring - Inspect the wiring connected the dishwasher. It is possible to have a loose connection or broken wire that will cause you to have no power. Check the connection box where the house supply connects to the dishwasher itself. This is the most common area for a failure. You may have some loose wire nuts.
Door Latch - If the door latch is not properly aligning with the catch, the switches inside my not be activated. This will cause you to not have any power to the control. The dishwasher will not operate if it thinks the door is open.
Other things that may cause this symptom - Your timer may be defective and not sending out the correct power. Your wash motor may have a reset button that has tripped and breaking the circuit to the timer. You may have a defective selector switch that is not allowing a certain cycle to start. Try selecting a different cycle to see if the unit starts.
Dishwasher Not Working (motor hums)
The Wash Motor may have become jammed and therefore cannot start. Remove the inside filter screen to gain access to the wash motor propeller and make sure there is nothing stuck there causing the jam.
The Drain Pump may have become jammed and this could also be causing the machine to not start a cycle. Some dishwashers use the same motor for draining as they do washing. They do this by reversing the direction of the motor. Again, you need to check the motor whether it's a separate drain pump or combined with the main wash motor. All it takes is a small piece of broken glass to stop the drain pump or wash motor from spinning.
The Drive Belt may be worn. Older style dishwashers use a belt like a washing machine. These belts can stretch over time. If the belt has become too stretch you will hear the motor run but nothing will happen. Replace the belt to repair this problem. There should not be much slack in the belt. If you can move the center of the belt more than an inch, replace it.
Water Valve - The dishwasher uses a single solenoid water inlet valve to allow water to enter into the tub when it calls for water. If the valve has become clogged you will experience this symptom. Check to make sure you have water getting to the valve and that the supply from the house is not turned off. Check for any loose or bad connections to the water valve. When you start a cycle the valve should read 120 Volts AC. If it's getting the voltage and not water is not getting in, replace the valve. If its not getting voltage you may either have a bad timer or the float is stuck
The Float Switch - This is a safety built in so that your dishwasher doesn't overflow. As the water level inside the dishwasher rises, so does the float. When it reaches a certain point, it breaks the power getting to the water valve. It is possible to have excess soap or dishes or whatever the case, cause the float to be stuck in the up position. These are located in the front of the dishwasher on either the right side or left side, usually covered with a cap. The switch is directly underneath the float. You will have to remove the kick panel to access the switch. The switch is an open or closed switch. When the float is up, the switch is open and you have not power to the valve. When the float is down, the switch should be closed and power should be getting to the water valve.
Drain Hose - The first thing you need to check is make sure there are not restrictions in the drain line going from the dishwasher to the sink drain. Remove the hose from both ends and blow through it. If you have just installed a disposal, make sure you popped out the plug in the side of it for the drain hose. I can't count the number of times that this has been the cause of the problem.
Drain Pump - You may have something stuck in the drain pump preventing the impeller from spinning. Clear the obstruction and make sure the motor still turns the impeller. If there is voltage getting to the pump and nothing is stuck inside and it won't spin, replace the pump.
The motor maybe be the problem if you dishwasher uses a motor for washing and draining. Check the motor as the instructions higher up on the page. It is possible that the timer has a bad set of contact causing not voltage to get to the motor. Remove the internal screens inside the dishwasher tub, take out the lower spray arm and make sure nothing is clogged up inside that area. This is another common area for clogs. Grease can sit in the sump and harden causing the no drain problem. Again, check the drive belt as stated earlier.