How to use a multimeter to test appliance parts

Your eyes and ears are often all you need to diagnose a problem within your appliance, but sometimes they aren’t enough. With so many small electrical components, you might need additional help to track down the part that has failed.

Enter the multimeter, an all-in-one measuring device and one of the most-used tools in our diagnostic tool kit here at AppliancePartsPros.com. A multimeter will let you know quickly whether or not an electrical part has failed and can help you find out if a part is starting to wear out.

With so many measurement options and accessories to consider, a multimeter may not seem like an easy tool for a beginner to use, but it’s actually quite easy! Stick with us, and we’ll walk you through how to get the most out of a multimeter.

If you need any replacement parts for your appliances, you can enter your model number at AppliancePartsPros.com to order them. Most orders arrive in just two business days, and we have thousands of free guides to show you how to install your new parts.

Disclaimer: The information in this article may not apply to your specific multimeter model. While we strive to offer helpful advice for all types of appliances, variations in models and configurations can lead to differences in usage recommendations. For the most accurate guidance, we strongly recommend consulting the use and care manual for your specific multimeter.

Read more: Appliance error codes: What are they & how can I fix them?

What is a multimeter?

A multimeter is a testing instrument designed to measure multiple electrical values, most often current (amps), voltage (volts), resistance (ohms) and continuity (another form of resistance). This information can then be used to diagnose faults and other issues in a variety of electrical systems within appliances. Multimeters are used by electricians, repair techs, and engineers in a variety of fields – they’re also potentially useful for DIYers like you.

Why should I own a multimeter?

A multimeter can cut down on the amount of time it takes to pinpoint issues with most major home appliances. You’ll find one particularly handy when troubleshooting and testing parts in just about every appliance in your kitchen and laundry room. You’ll notice testing steps in nearly all of our troubleshooting guides for electric ranges, washers, dryers, dishwashers and refrigerators.

Want some specific examples? Head over to our blog and search for the word “multimeter.” You’ll find a ton of guides that suggest using one to troubleshoot the most common appliance issues. 

Read more: How To Find Your Appliance’s Model Number

What does a multimeter test for?

You’ll typically be checking appliance parts for continuity, resistance or voltage. 

Here’s an overview of each type of test:

Resistance

Measured in Ohms (Ω). Measures the amount of difficulty an electric current has when it travels along a wire or another conductor. Resistance testing is used to verify the actual resistance value of resistors matches the specified or labeled resistance. It can also identify if a resistor is open (infinite or OL) or shorted (0 resistance). 

Common parts that can be checked for resistance include heating elements in electric stoves, ovens and dryers as well as windings inside electric motors, wiring, printed circuit boards (PCBs), diodes and transistors.

Continuity

A smaller resistance measurement. You can test a switch for continuity to see if it’s making or breaking the electrical circuit as expected. Continuity testing can also test relay contacts to make sure they’re closing the circuit when energized. 

Breaks, shorts, or poor connections in wiring harnesses, electrical cables, and cords can also be tested this way, as continuity testing checks for an uninterrupted path for electrical current through a wire or cable.

Voltage

Used to test the power that’s actively present in a live electrical circuit or appliance part. This can help diagnose issues with power supply circuits, control boards, and more. 

Live voltage testing is also used to measure the voltage present at the output of power supplies like receptacles and transformers. This can help you determine if the power supply circuit and electrical outlet is delivering the correct amount of voltage to an appliance. For example, dryers and ranges require 240 Volts AC to work. If you test the voltage and find that only 120 Volts AC is going to the machine, then you know that there’s a problem with the outlet, which a qualified electrician would have to fix.

LIVE VOLTAGE WARNING: To test live voltage, the appliance needs to be plugged in and powered on. Always be very careful to protect yourself from electric shock, which has the potential to cause serious injuries. Don’t ever test live voltage if you’re uncomfortable using a multimeter.

Read more: How To Safely Move Your Appliances

Which multimeter should I buy?

Multimeters come in a variety of shapes, sizes, and styles, and there are a wide variety of accessories for sale that expand what they can measure. The options can be a bit overwhelming, but you don’t need a top-of-the-line model with tons of options for DIY troubleshooting.

For our purposes as appliance repair experts, a basic digital hand-held model that measures amps, volts, and ohms is enough for most everyone. 

Analog multimeters tend to be more affordable, but digital readers are more accurate and easy to read than their needle-based counterparts. The smaller size also makes them much more convenient.  

Safety tips for using a multimeter 

Keep in mind that there’s always the potential for serious injury when working with electronics, especially if they’re powered, so take care when testing your appliances! Here are some tips to keep you safe and minimize the risk of electric shock or damage:

• Before you start any electrical test, refer to the manual for your multimeter and the appliance you want to test. Check for any safety guidelines specific to the test you will be running and follow them. You’ll usually want to keep your appliance’s technical sheet nearby anyway so you can reference appropriate reading ranges.
• Test the multimeter before each use to make sure it’s working. To do this, set the meter to resistance (Ohms Ω). Make sure the black lead is plugged into the “common” port and the red lead is plugged into the Ohms jack. Gently tap or touch the leads together. Your meter may make a beeping sound at this point. If the reading on the meter screen is greater than 0.5 ohms, the probes need to be replaced.
• Wear protective, insulated work gloves to further protect yourself from electric shock.
• Only use a multimeter in a dry area with dry parts and dry hands. 
• Never use a multimeter if the meter leads are damaged in any way. If the insulation is cracked, crumbling, or worn out, you can seriously injure yourself.
• While it’s generally safe to use multimeters on equipment that are still receiving power, make sure that the voltage or current provided doesn’t exceed the tester’s maximum rating. Double-check your multimeter’s rating and look into how much power the equipment you’re testing will be putting off.
  
• Never touch the metal portion of the multimeter’s leads when testing an appliance or internal component’s live voltage.
  
• If you’re measuring resistance, the equipment or component you’re testing should be de-energized – that is, totally disconnected from any power source. If the part is still receiving power, at best you will receive an incorrect reading, and at worst you can damage your multimeter and injure yourself.
  
• Electrical work takes expertise! If at any point in your diagnostic or repair process you don’t feel confident in your ability to safely complete a task, stop and call a professional repair technician for help.

Read more: How to Protect Your Appliances in a Power Outage

How to use a multimeter

For the most part, all multimeters work in pretty much the same way. Your tester most likely has a central knob and two meter leads, one black and one red, as well as a few other buttons and ports.

When testing appliances, you’re mostly going to be using the center knob and meter leads, and every test looks about the same:

1. Use the knob to select the test function – current, resistance, continuity, voltage etc. – and, if necessary, the range for the test.
2. Touch the leads onto the part’s wire ends or terminals to take measurements. If this is done correctly, the device will report its reading on the screen. It may beep if it detects continuity.
3. If you’re doing any test other than continuity (which is generally a simple yes/no state), your next step is to reference your appliance’s tech sheet or manual. This should include a table listing the acceptable readings or ranges for the part you’re testing. If the reading you’re getting is off by more than 10% of the acceptable range, the part is likely faulty.
   

Here’s a general example of how to use a multimeter to test an electric oven’s temperature sensor:

1. Set the multimeter to measure resistance (in Ohms Ω).
2. Touch the meter leads to the terminals on the back of the sensor.
3. Reference your range’s technical sheet. There should be a table that converts Ohms to temperature. If the reading you got matches the temperature in the oven when you did the test, your temperature sensor is working. If it’s way off, the sensor is malfunctioning.

More information

Multimeters aren’t nearly as complicated as they might seem. Now that you know how to get the most out of your multimeter, remember us when you discover a part that needs to be replaced! 

AppliancePartsPros.com has over 2.1 million quality OEM parts that can be shipped to your door in as little as two days to make any home repair a snap! We have thousands of free resources to show you how to install your new parts.

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