Dishwasher Repair

 

This Fix-It Guide on dishwasher repair tells how a dishwasher works, what often goes wrong, how to identify a dishwasher problem, and what parts and tools you will need to fix it. It then gives  step-by-step instructions for how to access dishwasher controls, how to check dishwasher detergent dispensers, how to clean spray arm(s), how to test a dishwasher heating element, how to test and replace door latch and switch, how to test the water inlet valve, how to test the drain valve mechanism and solenoid (if so equipped), how to inspect dishwasher float and float switch, how to test dishwasher pump and motor assembly, how to service a dishwasher door springs and cables, and how to replace dishwasher door gaskets. It also refers to other Fix-it Guides for further repairs.

How Does a Dishwasher Work?

A dishwasher is a major appliance designed to clean dishes, silverware, pots and pans, and other kitchenware. It delivers water through the water inlet into the tub while the detergent dispenser releases detergent in stages to clean the dishes. The heating element warms the solution and a pump channels the water to spray arms that spray and clean the dishes. When the wash cycle is complete, clean water is sprayed to rinse off the detergent. The heating element is also used to dry dishes. Some dishwashers have upper and lower spraying arms while others have a single arm. Also, some dishwashers have a dispenser that adds a rinsing agent to the rinse water.

Built-in dishwashers are installed under countertops with permanent wiring and plumbing connections. Portable models have a flexible coupler that connects to the sink faucet and a drain tube that runs through the sink drain. Power is supplied through a 120-volt plug.

Fix-It Tip

Help your dishwasher do its best job. Check the owner’s manual to make sure you are loading the machine correctly. If your water is high in minerals, use a little extra detergent. Make sure the dishwasher is getting sufficient water from the supply line.

What Can Go Wrong with a Dishwasher?

dishwasher Dishwasher Repair

Components of a typical dishwasher.

With all that water running through it, a dishwasher on the fritz can damage flooring and cabinets, so maintenance and troubleshooting is a good idea. What can cause problems? Switches and motors can fail. Dispensers and spray arms may become dirty and clogged. The heating element may malfunction. The door latch may be out of adjustment. Drain valve parts may need replacing. The drain hose may be clogged.

How Can I Identify a Dishwasher Problem?

  • If the dishes are dirty or spotted, check your owner’s manual for loading recommendations; test the selector switch and the timer motor. Inspect the dispensers (see below), clean the spray arm (see below), and test the water temperature (see Test a dishwasher heating element, below).
  • If the dishwasher drains during the fill cycle, check the water supply line. Check the door latch and door switch (see below), inspect and clean the spray arm, inspect the float and float switch, and test the inlet valve solenoid (see below).
  • If the motor doesn’t run, make sure there is power to the electrical receptacle and that there is not a blown fuse or tripped breaker at the electrical service panel. Test the timer motor; resistance should be about 3,300 ohms. Inspect the float and float switch (see below) and service the water inlet valve (see below).
  • If the motor hums, but doesn’t run, test the timer motor. Also check the door latch and door switch (see below) and test the motor .
  • If you have poor water drainage, test the timer motor (see below), inspect the drain hose and spray arm (see below), and test the drain valve solenoid (see below).
  • If the dishwasher leaks around the door, adjust the door latch (see below), service the door springs (see below), or replace the door gasket (see below).
  • If the dishwasher leaks from the bottom, inspect the drain hose and spray arm (see below), then check the water inlet connection (see below).
  • If the water doesn’t shut off, test the drain valve (see below).

Fix-It Tip

Most of the key components of a built-in dishwasher are accessible through the front panels. That means you probably won’t have to remove it from the cabinet to figure out–and fix–what’s wrong with it.

What Do I Need for Dishwasher Repair?

The first place to start looking for replacement parts is your local appliance parts supplier. You also can check with the manufacturer and aftermarket suppliers. The tools you may need to fix a dishwasher include these:

  • Screwdrivers
  • Multimeter
  • Wrenches
  • Pliers
  • Nut driver
  • Thermometer

What Are the Steps to Dishwasher Repair?

Caution!

Before working on a dishwasher, always turn off power to the machine. Built-in models are plugged in under the sink. If you can’t easily access the plug, turn off the appropriate breaker in the electrical service panel. Also remember to locate the water supply shutoff and turn the water off before beginning repairs.

Access dishwasher controls:

  1. Unplug the dishwasher or turn off power at the electrical service panel.
  2. Remove retaining screws on the interior door and on the front of the control panel, then remove the interior door panel.
  3. Remove the control panel cover by removing clips that secure the cover to the door.
  4. As needed, also remove retaining screws to remove the lower front panel and expose the controls.

Check dishwasher detergent dispensers:

  1. Remove caked-on soap around the dispensers, check the covers and replace any gaskets that are damaged.
  2. Remove the interior door panel (see above).
  3. As needed, remove the rinse agent dispenser held in place by tabs or other fasteners. Check the dispenser for stuck or broken parts and replace any damaged parts.
  4. To test an electrically operated dispenser for continuity, first unplug or otherwise disconnect the dishwasher from the power source. Then use a multimeter set on RX1 (resistance times 1) to test the unit, replacing it if the reading is infinite.

Clean dishwasher spray arm(s):

  1. Either unplug the dishwasher or turn off power at the electrical service panel.
  2. Slide out the lower dish rack.
  3. Rotate all spray arms and lift the spray tower to make sure that they move freely. If they don’t, or if the arms wobble excessively, tighten or replace them.
  4. To replace a spray arm, unscrew the spray tower clockwise by hand and remove it along with any fasteners and washers.
  5. If the spray arm is not replaced, clean the holes in the existing spray arm and tighten.

Test a dishwasher heating element:

  1. During the unit’s first cycle, open the door and measure the water temperature with a meat or candy thermometer. If it is below 140°F, test the element.
  2. Before working on the heating element, unplug the dishwasher or turn off power at the electrical service panel.
  3. Use a multimeter set to RX1 (resistance times 1) to test the heating element. Look for a reading other than infinity. Also place one probe on a terminal and the other on the element’s metal sheath to check for continuity to ground (not good!). Replace an element that fails either test.

Test and replace a dishwasher door latch and switch:

  1. To adjust the door latch, loosen the retaining bolts with a nut driver, slide the latch in or out, and tighten the bolts.
  2. If the door latch closes securely and the machine will not run, test the switch.
  3. Before continuing, unplug the dishwasher or turn off power at the electrical service panel.
  4. Set a multimeter to RX1 (resistance times 1) and test the switch for continuity. The meter should indicate continuity with the switch button pushed in, and an open circuit when it’s out. Replace the switch if your test results are different.
  5. To replace the switch, remove the door switch retaining bolts (see step 1) and remove the switch assembly. Install a new door switch and reconnect the switch wires.

Test a dishwasher water inlet valve:

  1. Remove the lower front panel (see above). Make sure the incoming water line and the hose that connects the inlet valve to the tub are securely fastened.
  2. Remove the wires from the inlet valve terminals.
  3. Set a multimeter to RX1 (resistance times 1). Touch a probe to each terminal. A good valve will show some, but not infinite, resistance.

Test a dishwasher drain valve mechanism and solenoid (if so equipped):

  1. Unplug the dishwasher or turn off power at the electrical service panel.
  2. Remove the lower front panel (see above) to inspect the motor. If it has four wires, the motor is reversible and has no drain valve to service. Otherwise, continue with step 3.
  3. Inspect the gate arm mechanism for free movement. Inspect the springs and replace them if they are missing or broken.
  4. Disconnect the wires from the drain valve solenoid. Set a multimeter to RX1 (resistance times 1). Clip a probe to each terminal on the solenoid and check for some, but not infinite, resistance (open circuit).
  5. If replacing the solenoid, detach and label wires, springs, and screws, then install an exact replacement unit.

Inspect a dishwasher float and float switch:

  1. Unplug the dishwasher or turn off power at the electrical service panel.
  2. Remove the lower front panel (see above). Make sure the clamp is secure and remove any kinks in the hose by hand.
  3. If necessary, replace a broken or badly kinked hose using pliers to squeeze the spring clamp, and pull off the hose.
  4. Disconnect the other end of the hose (under the sink), cut and install a new hose of the same length and size.

Test a dishwasher pump and motor assembly:

  1. Unplug the dishwasher or shut off power at the electrical service panel.
  2. Remove the lower front panel (above) and manually turn the motor fan blades. If they don’t move freely, look for obstructions or call for service.
  3. Disconnect the motor wires from their terminals.
  4. Set a multimeter to RX1 (resistance times 1) and attach a probe to each motor wire terminal. The motor should show little resistance.
  5. Check the ground connection by placing one probe on the bare metal housing of the motor and the other probe on each terminal in turn. There should be no reading. If the motor fails either test (in steps 4 and 5), call for professional service.

Service dishwasher door springs and cables:

  1. Unplug the dishwasher or shut off power at the electrical service panel.
  2. Remove the lower front panel (see above). Inspect the cables and springs. Replace damaged springs and cables in pairs to ensure proper tension.
  3. Remove a damaged cable or spring and replace it following manufacturer’s instructions.

Replace dishwasher door gaskets:

  1. Open the dishwasher door and remove the dish racks.
  2. Inspect the gasket for damage or brittleness and replace as needed.
  3. Remove the gasket with a screwdriver or putty knife and install one of the same type, diameter, and length. The unit owner’s manual may include a part number to help in tracking down a replacement gasket.

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