Common Repairs for an Ailing Dishwasher

A technician diagnosing and repairing a broken dishwasher.

Dishwashers are incredibly durable machines. In many cases, it's only a change in decor that brings about a replacement, as they can take years of daily use. All in all, the dishwasher is an ingenious appliance that uses both electricity and water to give us years of dependable service. Of course, that doesn't mean things never go wrong with them.

You'll want to check the most common malfunctions first, since they are easiest to identify and deal with. Here are some common problems you may face with your dishwasher, ways to find out what's causing it, and how to fix it. As with all electrical troubleshooting, you will need a VOM (volt-ohm meter) to check certain parts. Remember, the power to the dishwasher needs to be always off when checking parts, unless otherwise stated. It's also helpful to keep a notebook nearby to record how things disassemble to make it easier to put them back together.

The Dishwasher Won't Turn on at All

With every electrical appliance, it pays to check the power at the source. Make sure the breaker is on first, then check the power at the dishwasher. If it's hardwired, go back and turn the breaker off. Open the dishwasher door, unscrew the screws holding it in place underneath the countertop, and shimmy the unit out. The junction box will be located at the rear, on the bottom. Locate yours, open it, and check the wires for corrosion, breaks, or loose connections. Check the interior of the box for any burn or "arc" marks as well. If everything is clear, turn the power back on and check for voltage by probing the black and white wires. If you get no voltage, the breaker itself may be bad.

If power isn’t the problem, the issue could be a bad door latch switch. Open the door's access panel and set your VOM to RX1. With the latch in the "open door" position, probe the two terminals. You should get a reading of infinity. Now close the latch and probe again; the reading should be zero this time or the latch switch will need replacement. If it's a matter of the latch switch just not closing, then you might only need to adjust the latch. Loosen and reposition it, then re-tighten. You want a nice, tight seal on the door when it's closed.

Next check the control timer motor. With the control panel off, disconnect the motor leads from the timer. Set the VOM to RX100 and clip the probes to the lead wires. If you get an infinity reading, or a very high resistance, then the motor is broken.

The Dishwasher Leaks From Underneath

Nine times out of ten, this is a hose problem. Check the drainage hose for cracks or loose connectors. If it's not the hose, then it could be one of these other causes.

If you see evidence of leakage at the gaskets in the heating element, they could be loose or bad. Simply unscrew the heating element and unlock it from its holders. Disconnect the leads and replace the gaskets, then reassemble. Check the tub for any rust spots next. Minor spots can be cleaned up and repaired with an epoxy approved for dishwashers. Purchase the epoxy at your local appliance store and follow the directions on the container.

The Dishwasher Is Running but There's no Water

The easiest thing to check in this case is the float switch, located in the base of the tub. First, make sure there's nothing obstructing it and that it lifts up easily. Check the power to the switch by probing the terminals with the VOM on RX1. You should get a reading of zero, or with the float raised, the reading should be infinity. If not, replace the float switch.

To check whether the malfunction may be a clogged inlet valve instead, turn off the water feeding the dishwasher and disconnect the hose, wires, and pipe from the valve. Remove the mounting screws, pull the valve out, and with needlenose pliers, remove the filter. Just clean the filter under running water and reassemble to fix this.

The Water Won’t Drain

The most common cause here is a dirty strainer. Many dishwashers have one that sits on the bottom, but some have a little raised part in the corner instead. Locate yours and check to make sure it's not clogged with food or debris. If that is all clear, check to make sure the drain hose hasn't been bent, kinked, or clogged.

My Dishes Don't Get Clean

Many times this is just bad detergent at fault. Some detergents are less powerful the longer they sit unused, so some new detergent may be all you need. It could also be the way you're loading the dishwasher. Make sure nothing is obstructing the spray tower or arms.

Sometimes, your water can be too cold. Don't run the dishwasher right after anyone’s just taken a shower or run a load or two of laundry in hot water. Or, if you have a water conditioner in your house, it may be time to refill it with salt.

Remember, these are just some of the most common problems with the most common solutions. With appliances, there are an infinite number of potential malfunctions you may face. Hopefully, yours will be one of the easy ones that can be solved with the help of this guide.

Tip: To save you even more time, and maybe a headache, be sure to have your dishwasher's make and model number when heading to the parts shop.