Most cleaning problems are caused by the dishwasher not getting enough wash water, so the water-inlet valve is often to blame. This valve is usually at the bottom left or right of the dishwasher, behind the lower access panel. It's the device with the main water line from the house, a rubber tube to the dishwasher, and two wires attached to it.
When a water-inlet valve is defective, you may hear the sound that's usually referred to as "water hammer." If the water-inlet valve is defective, you need to completely replace it.
Dishwasher Water Inlet Valve Replacement
Be sure to read and understand any instructions that come with the new water inlet valve.
Step 1. Disconnect the dishwasher from its power source.
Note: Dishwashers are usually wired directly to the home’s electrical system. To disconnect the power, switch off the circuit breaker or remove the fuse for the electrical circuit the dishwasher is attached to. Try to turn the unit on after disconnecting the power to be sure you were successful.
CAUTION: If you’re not sure you’ve shut off the power properly, DO NOT CONTINUE. Call a qualified appliance repair technician to complete the repair.
Step 2. Turn off the water supply to the dishwasher. This is usually underneath the kitchen sink or in the basement or crawlspace near the location of the dishwasher. Pliers may be helpful here.
Note: If there are no shut-off valves, you must shut the water off at the main water supply valve for your home.
Step 3. Remove the lower panel(s) of the dishwasher. These are usually held by 2 to 4 screws at the upper and lower corners of the panel(s).
The inlet valve is usually near the front of the dishwasher. Attached to the valve you’ll see: 2 or 4 wires, the water supply line from the house and the water feed line that goes to the dishwasher.
Step 4. Remove the household water supply line from the valve. The line is usually secured with a brass compression nut. The water supply line is usually copper or braided stainless steel.
CAUTION: Water supply line may be hot.
Step 5. Remove the fitting from the valve the water supply line was attached to. This fitting may be very difficult to remove. It may help to put the valve into a vice in order to remove the fitting. If you cannot remove it, replace it. The fitting is not an appliance part but a plumbing part that is available at most hardware stores.
Step 6. Remove the screws holding the valve to the dishwasher frame.
Step 7. Label the wires to the valve so you’ll be sure to reattach them correctly.
Step 8. Remove the wires from the valve.
Step 9. Remove the clamp on the black rubber water discharge tube and pull the tube off of the valve.
Step 10. Reinstall the old fitting (or a replacement fitting if necessary) onto the new valve the water supply line was attached to. Use Teflon tape or pipe joint compound as a thread sealant. Make this fitting tight to prevent leaks. Make sure that the fitting points in the same direction as the old one so that the water supply line will meet up with it properly.
Step 11. Install the new valve in the reverse order of the removal instructions.
Note: The water supply line is under high pressure. Be sure to tighten the fittings properly.
Step 12. Turn on the water to the machine, and check for and correct any leaks.
Step 13. Reinstall the access panel(s). Restore the power to the dishwasher and test.
Note: You may have to let the dishwasher run a few minutes before it reaches the next water fill cycle.