How to Repair a Dishwasher

Get solutions to common dishwasher problems.

Save money doing the repairs yourself

Do your dishes come out spotted and stained? Have you noticed a puddle of water on the floor? Does your dishwasher simply fail to start up? If so, you're not alone. These three complaints make up the vast majority of dishwasher problems. But now the good news: You can solve these problems about 90 percent of the time without calling for professional help. Instead of paying $70 for a service call, do the work yourself in less than 30 minutes. Most repairs involve only routine maintenance and require no special tools or skills and little or no expense.

In this article, we'll tell you how to pinpoint the causes of most problems, then walk you through simple maintenance steps to correct them. In most cases, even a time-pressed novice can get the dishwasher working again within a half-hour.

We're using a GE dishwasher for our demonstration, but most brands and models have a similar design. Pull out the owner's manual and compare it with our illustrations to help identify and locate key parts. It will also help you identify part numbers when you need them. If you can't find the manual, you can order one from the appliance manufacturer. Appliance dealers can supply the customer service number for your brand.

How a Dishwasher Works

A dishwasher doesn't fill like a clothes washer. Instead, 2 to 3 gallons of water flood the lower portion of the tub, where it mixes with the detergent and is pumped through the rotating spray arms onto the dishes. The wash water drains and is replaced by fresh water to rinse the dishes.

The cycle often repeats several times. A timer regulates the water volume. A heating element near the bottom raises the water temperature to 140 to 160 degrees F. The element also helps dry the dishes after the wash and rinse cycles are completed.

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Problem 1: Your dishes don't come out clean

A. Review the basics (5 minutes)

  • Are you overloading your dishwasher? Check the manufacturer's instructions to make sure you're loading it right.
  • Does silverware drop below the lower basket? The spray arm can't spin if obstructed.
  • Are you using the proper dishwasher detergent?
  • Do you routinely scrape food bits off dishes before loading them into the racks? (Rinsing is not necessary.)
  • Are you using a special rinsing agent if your water is hard (highly mineralized)? Hard water can leave a film on the dishes.

Tip: Adding a water softening system can dramatically improve dishwasher performance.

  • Is the water temperature high enough? This can be a complex issue.

We recommend that your household water heater be set no higher than 120 degrees F, both to help prevent accidental scalding and to maintain energy efficiency. Many dishwashers have heating elements that boost the temperature to about 140 degrees. However, some dishwashers don't have a heating booster and require household water at about 140 degrees. So first check the owner's manual for the recommended water heater setting.

If your dishwasher requires140-degree water, check the temperature of your hot water at its current setting. Put a meat thermometer in a glass and fill it at the kitchen faucet with water at its hottest point. If the temperature reads less than 140 degrees, you'll have to either risk raising the water heater setting (we don't recommend it) or consider buying a different dishwasher. But check the maintenance steps below first to make sure poor cleaning isn't caused by other factors. In any case, consult a service pro before making a buying decision.

B. Clean the spray arm (10 minutes)
Twirl the spray arm to make sure it spins freely. Also check the holes in the spray arm for debris. If you spot debris or the spray arm doesn't spin, remove the spray arm and clean it (Photos 1 – 3).

First take out the wire baskets by removing either a cap or pin at the end of the sliding tracks. Don't fret about a little water on the bottom of the tub. It's supposed to be there. It keeps the seals in the pump and in the motor assembly damp. If they dry out, they'll crack and leak.

The spray arm cap twists off with a clockwise turn, just the opposite of a regular screw (Photo 1). Twist ties, rubber bands and plastic and paper often show up in the spray arm. You might have to use a needle-nose pliers to pick them out. The pump usually sucks up most of this stuff, but if you hear a sudden loud grinding sound while running the dishwasher, something like broken glass might be stuck in the pump intake. Unscrew and remove the pump cover (Photo 2) to check it out.

C. Clean the float switch (5 minutes)
The float switch may not be a problem, but it takes only a few minutes to check it, so open it up and clean it anyway (Photos 4 and 5). Debris can cause the float to stick in the raised position, which prevents the tub from filling. If the water doesn't reach the right level (just covering the heating element), the dishwasher won't clean well. See the next section for how to check the water level.

On most models, you'll find the float switch in the lower front of the tub (Fig. A and Photo 4). Ours has a cover, but some don't. You may have to use a small, flexible brush or pipe cleaner to clean those without a removable cover. When clean, the float should slide up and down freely.

D. Clean the valve screen (30 minutes)
One common symptom of a clogged intake valve screen is a low water level during the dishwashing cycle. (Low water could also indicate a clogged float switch, but you've already taken a few minutes to check it.) So before going through the somewhat more complex steps for cleaning the intake valve screen, check the water level.

Close the door, turn on the machine and run it until it's done filling during its second cycle. Then open the door (the machine will automatically shut off), and check the water level. If the water doesn't come up to the heating element, it's too low. Close the door and let the machine cycle on through. Then proceed to clean the intake valve screen (Photos 6 – 9).

You'll have to unhook several wires, so always begin by turning off the electrical power to the dishwasher at your main panel. Turn off the water supply to the dishwasher as well. Usually the shutoff is at the hot water supply line under a nearby sink. The inlet valve is usually mounted on the underside of the dishwasher near the front.

You have to remove the lower panels (Photo 6) and disconnect the valve (Photos 7 and 8) to get at the valve screen, a wire screen mounted within the body of the valve itself (Photo 9). If the wires don't pull off readily, push the small spot in the center of the connector to release them. And mark one wire and its terminal with tape so you can get them back on the same way. (In this case it doesn't matter, but it's a good practice anyway.)

Tip: Keep a rag handy. You'll have to mop up a bit of water when you unhook the copper supply tube.

Some pros prefer to simply replace the valve on old machines to avoid problems in the near future. Look under “Appliance Parts” in your Yellow Pages for sources. Call first.

Tip: Stick the end of the supply tube into a pan and turn on the water supply briefly to flush out sediment before reconnecting the supply tube.

Now run a load of dishes. If the dishes still don't come clean, call in a service expert to find the problem.

Figure A: Dishwasher Details

Refer to this illustration to find the parts and their locations inside the dishwasher.

This illustration shows the dishwasher parts and components.
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Problem 2: Water pools on the floor—door leaks

A. Pinpoint the source (5 minutes)
A poorly sealing door causes most leaks, and this section concentrates on solutions for this problem. Check for a bad seal when washing the next load of dishes by looking for drips directly under the door. If you find moisture, go to the next step. If you don't find any and a puddle appears, unscrew the lower front panels and look for drips around hoses and other parts. Sometimes you can tighten a hose connection, but most repairs for these types of leaks are difficult. We won't cover these repairs in this article.

B. Eliminate simple door leak causes first (10 minutes)

  • Check the gasket (Photo 10). If you can't find obvious damage, simply clean it with a sponge and all-purpose household cleaner.
  • Clean the float switch. A float switch stuck in the lowered position will cause the tub to overfill. See Photos 4 and 5 for cleaning directions.
  • Use the detergent specified for dishwashers only. Hand dishwashing liquid will over-foam, produce leaks and make your kitchen look like an old “I Love Lucy” episode.

C. Adjust the door (5 minutes)
Test your door to see if it needs adjustment. First, close and latch it. It should fit tightly. If you can jiggle it, it's too loose. Second, run the dishwasher and listen. Then push in on the door. If the sound decreases, the door is too loose.

Most dishwashers have an adjustable latch plate centered at the top of the frame (Photo 11). Adjusting this plate to tighten the door will help the gasket seal better. Adjust it in small increments, testing the door fit after each adjustment. The door should fit snug, but not so tight that you have to force or bend the latch.

D. Replace the door gasket (20 minutes)
If the leak around the door persists, the gasket is probably cracked, brittle or worn. Buy a new door gasket from an appliance parts store. Some types are tricky to install.

Read the instructions that come with the new gasket. Observe how the old one fits when you pull it out. And a couple of tips: Rub petroleum jelly on flanges to help them slip in easier. And soak them in hot water to soften the kinks and help prevent creases. If you can't make the new gasket watertight, don't hesitate to call a service pro for help.

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Problem 3: Doesn't start

A. Check the power supply (2 minutes)
All dishwashers should have a nearby shutoff, either a switch above the sink or a cord you can unplug under the sink. If the switch is off, turn it back on. Or plug the machine back in. If it doesn't start, check the circuit breaker or fuse at the main electrical panel to make sure it hasn't tripped. The dishwasher should have its own circuit.

B. Spin the motor (10 minutes)
Sometimes the motor sticks and won't turn, especially if you haven't used the dishwasher for a while. One sign of this problem is a humming sound without any other action. To get things going again, remove the lower panels (Photo 6) and reach under and spin the motor by turning its fan blades by hand (Photo 12). You must turn off the electrical power at your main panel to do this safely. If the blades don't turn freely, call in a service pro to diagnose the problem.

If the blades spin and the dishwasher still doesn't start when you turn the power back on, you're faced with a more complex problem—perhaps a bad switch, a clogged pump or bad wiring. Call a licensed electrician or a service pro to troubleshoot these types of problems.

Pick Up Your Phone for Advice

Don't hesitate to call an appliance repair pro or the salesperson at the parts store to ask for advice. They're usually friendly and helpful, and will often walk you through your problem to a simple solution, especially if you've already taken a few moments to try the simple solutions covered in this article.

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