Dishwasher Motor Not Running? Test the Motor and Capacitor

Safety first: disconnect power

Before touching any electrical part of your dishwasher, turn off the circuit breaker or unplug the unit. Motors and capacitors store electrical charge even after the appliance is off, so wait at least five minutes after disconnecting power before opening the access panel. Capacitors can retain a charge for a long time; discharge them with an insulated screwdriver before touching the terminals.

Also note that dishwashers are covered by federal appliance standards (see the Department of Energy's program for context). Always follow the manufacturer's service manual and local electrical codes.

Identify the motor type

Most dishwashers have two motors: a wash motor that drives the spray arms and a drain motor that pumps out water. Some newer models use a single reversible motor or a direct-drive motor without belts. Older models may use a belt connecting the motor to the wash pump. The test procedure is similar, but you need to locate the correct terminals on each motor.

If you're unsure about the layout, our article on dishwasher motor types explains the differences. For a quick orientation, you can also check the best built-in dishwashers guide to see what types of motors are common in current models.

Test the motor winding

The motor winding is a series of copper coils that create a magnetic field. If the winding has an open break, the motor will not run. Use a multimeter set to the ohms (Ω) function to test continuity.

With the power off, access the motor terminals. Typical motors have three or four terminals: common, start, and run. Measure resistance between each pair. A healthy winding shows a low, but non-zero resistance (for example, a few ohms to tens of ohms). If the reading is infinite (OL), the winding is open and the motor needs replacement. You may need to remove a cover or bracket to reach the terminals; the wiring diagram on the motor label helps identify which terminal is which.

If the dishwasher has a thermal fuse or overload protector, test that component as well. A blown thermal fuse will also prevent the motor from starting. See our guide on thermal fuse diagnostics for more details.

Test the capacitor

Many dishwasher motors use a start capacitor to give the motor an initial boost of torque. A faulty capacitor can cause the motor to hum but not spin, or to fail to start altogether. The value is usually in microfarads (µF) and is printed on the side of the capacitor.

Discharge the capacitor first by placing a screwdriver across its terminals (after disconnecting power). Then set your multimeter to capacitance mode. Compare the reading to the value printed on the capacitor. If the reading is significantly lower, the capacitor is weak or dead and should be replaced.

If your multimeter lacks a capacitance mode, you can do a simple resistance check: the reading should start low and rise toward infinity as the capacitor charges. A constant low reading or an open reading indicates a short or open capacitor.

Test the start relay

Some dishwasher motors use a start relay (also called a potential relay) to switch the start winding out of the circuit once the motor reaches speed. A stuck or failed relay can prevent the motor from starting or cause it to run slowly.

The relay is usually a small rectangular box mounted near the motor. Remove it and inspect for signs of burning or melting. Use a multimeter to check for continuity across the relay contacts. If the contacts are closed when they should be open, or vice versa, replace the relay. You can also test the relay coil with an ohmmeter to see if it has continuity.

If you find the relay is fine, the problem might be the control board not sending voltage. Our control board reset guide can help you decide whether the board needs attention.

Other causes and next steps

If the motor, capacitor, and relay all test good, the issue could be a jammed impeller or a blocked drain pump. For wash motors, a stuck spray arm bearing can also bind the motor. Check for debris in the sump and impeller area. Also check the water level switch; if the dishwasher doesn't sense enough water, it may not energize the wash motor.

For drain motors, a clogged drain line or a foreign object in the pump will make the motor work harder and eventually fail. See our dishwasher not draining troubleshooting guide for a systematic check.

If you have tested everything and the motor still will not run, the motor itself is likely bad. Replacing a motor can be costly; compare the repair cost against the price of a new dishwasher. Our best built-in dishwashers and best countertop dishwashers lists can help you find a reliable replacement.

When to call a professional

Working on a dishwasher involves electricity, water, and moving parts. If you are not comfortable with a multimeter or unsure of the diagnostic steps, call a licensed appliance technician.

Before you do, check if the dishwasher is still under warranty. Many manufacturers offer in-home service, and a DIY mistake could void the warranty. A technician can often diagnose the problem in a few minutes. Also, if your dishwasher is over 10 years old, a major motor failure might be a sign it's time for an upgrade. Our repair vs replace decision guide can help you weigh the options.

What to do based on your test results

Questions

How do I test a dishwasher motor with a multimeter?

Disconnect power, access the motor terminals, set the multimeter to ohms, and measure resistance between each pair of terminals. A low, stable reading indicates a good winding; an infinite reading means an open winding.

What resistance should a dishwasher motor read?

There is no universal value; it depends on the motor design. Consult the service manual for the exact specification. Generally, you expect a low resistance (a few ohms to tens of ohms) that is consistent across winding pairs.

Can a bad capacitor cause a dishwasher motor not to spin?

Yes. A weak or open start capacitor prevents the motor from getting the extra torque needed to start, so it may hum or not run at all. Testing and replacing the capacitor is a common repair.

Should I replace the motor or the whole dishwasher?

If the motor is expensive and labor costs exceed half the price of a new dishwasher, replacement usually makes sense. For a dishwasher older than 10 years, a new ENERGY STAR certified model will likely save water and energy in the long run.

Can I test the motor without removing it?

In many cases, yes. Once you access the control area and locate the motor terminals, you can test continuity and capacitance with the motor in place. However, if the motor is hard to reach or is part of a sealed assembly, you may need to remove it for a thorough inspection.