How to test a dishwasher's water inlet valve:

Testing a water inlet valve
Note:
Disconnect the power source to your dishwasher before you conduct this or any other test. Either unplug the unit from the wall outlet, remove the appropriate fuse from the fuse box, or flip the appropriate breaker in the circuit breaker panel.

Locate your dishwasher's water inlet valve. It should be located behind the lower kickplate panel in either the right or left corner. There will likely be two screws either on the top of the panel, or on its bottom. Remove these two screws, and then remove the kickplate. On some dishwasher models, the door has to be opened in order to gain access to, and remove the kickplate's screws. Close the door before you remove the kickplate panel.

You will be able to identify the water inlet valve by the hoses that connect to it. There will be one hose feeding water from the house to the water valve, and another hose leading from the water valve that carries water away. Now is a good time to inspect your dishwasher's hoses, to make sure they aren't responsible for any water flow problems. Make sure the hoses are securely connected to the valve. Also check to make sure there are not kinks in the hoses. Kinks can impede the flow of water.

There will be two wires connected to the water inlet valve. If your dishwasher's water inlet valve has two solenoids, then there will be four wires. Label the wires so that you will be able to correctly reconnect them later. The wires are connected using slip-on connectors. Grasp the connectors and pull on them firmly in order to disconnect the wires from the valve's terminals. Do not pull on the wires themselves. You may want to use a pair of needle nosed pliers to help you.

Use your multitester to test the valve for continuity. Set the device to the ohms setting x 1. Touch each of the meter's probes to a terminal. If you receive a reading of infinity, it means the valve's solenoid is faulty and the valve needs to be replaced. If your valve has two solenoids (four terminals), test the second pair of terminals in the same manner. If either pair of terminals receives a result of infinity, replace the water inlet valve.

You do not have to remove the water inlet valve from the dishwasher in order to test it. Just make sure power is not getting to your dishwasher before you conduct the test.

Interestingly enough, it is entirely possible for your water inlet valve to pass the continuity test and still need replacing. This is because sometimes the valve itself is faulty, but its solenoids are not. For instance, a leaky valve may pass the continuity test, but because it is leaking, it should be replaced anyway. The same applies to valves that are filled with debris. The debris may be what is causing the valve to not function properly. If you are unable to clean out a debris-filled water inlet valve, you will have to replace it.