Not every seemingly damaged device requires a service call. The most common problems with home appliances are mechanical in nature. You may have broken or worn components (such as switches or motors). Loose wires or poor connections can also cause problems that are easy to fix. Any homeowner can learn how to troubleshoot and fix electrical problems with appliances if they want to. Read on for some easy troubleshooting tips!
Editor's note: We do not claim final authority on any advice you adopt online. Before working on any wires, turn off the circuit breaker and use a non-contact voltage tester and/or multimeter to verify that power is off. Please take all safety precautions to prevent electric shock and/or consult a professional if you do not understand what you are doing. Electricity is no small matter! You also want to make sure that all local and national building and electrical codes are followed.
Most household appliances take AC voltage, which the utility company supplies to your home, and uses it to heat, light, turn a motor, or all three at the same time. But when a device stops functioning, sound troubleshooting methods come in handy. Troubleshooting electrical problems and even tracing circuit breakers requires access to basic tools.
For example, you can use functions on a tool such as an Amprobe multimeter to check that each circuit component is getting the correct voltage, and even the condition of components and connections. It helps to equip with electrical problems. To ease this pain, you should have the following tools:
- NCV – Non-Contact Voltage Detector (determines if power is flowing to the circuit for your safety)
- Digital Multimeter (measures AC and DC voltage and continuity – if a wire is open)
- Screwdriver (Phillips and flat head)
- Basic Wire Strippers
- Clamp Meter (to check current draw – this is for more advanced troubleshooting and repairs)
How to Solve Electrical Problems Step-by-Step
Here's a recommended step-by-step troubleshooting method you can use to isolate and fix electrical problems near any appliance problems using a digital multimeter (DMM) and a few basic tools:
1. Check the AC power voltage
Believe it or not, some problems start at the source. Always make sure your outlet or power supply has the proper AC voltage.
To measure the AC mains voltage at the outlet, first set the DMM (Digital Multimeter) function switch to AC Voltage (VAC). If necessary, select a range that is greater than the voltage you wish to measure (greater than 120 volts). Autoranging meters automatically select the most appropriate range for you. Next, connect the test leads (red and black) to the voltage (V) and common (C) terminals on the meter.
Use the red multimeter lead to test the "live wire", and the black test lead to test the neutral or ground wire. Carefully insert the meter's red probe into the "hot" slot of the socket. This is usually the "short" or smaller slot. The black probe goes into the other vertical or ground slot of the receptacle.
The meter should read between 116 and 124 volts. A device's power cord is usually terminated with three wires: black, white, and green. Black (or less commonly red) is usually the "live", white is the "neutral", and the green wire should be ground.
You should also read that there is almost no voltage between the neutral wire (long slot) and the ground hole.
Low or No Voltage Troubleshooting
If you don't measure voltage at the outlet, check to make sure the circuit breaker or switch that controls the outlet is turned on. Also, make sure the probes are fully seated in the sockets. You may need to angle them or move them around to be sure. If you do detect voltage at the outlet, there may be a problem with the power cord. That will be your next test.
However, if your measured voltage is much lower than the expected ~120V, there may be a problem with a disconnected neutral (white). Since most of the time the wires don't "break in the middle", you may want to check the neutral wire (white) for corrosion or a disconnect at an outlet or switch on the same circuit. Always turn off the power before looking for a damaged neutral.
2. Check the power cord
Over time, sometimes due to accidents or bending, the inner conductors in a power cord can break while appearing perfectly fine on the outside. To check the power cord, first unplug it from the outlet. For the next part, you will need access to the internal connections on the device. Never test any wires while the appliance is still connected to an outlet!
Set the multimeter to the resistance or "ohms" function and measure the resistance between each prong of the plug and the point where the power cord connects to the appliance. The flat narrow blade on the plug should connect to the black wire. The flat, wide blade is connected to the white wire. The round pin connects to the green wire.
A good power cord has a resistance of less than 1 ohm from the plug to the end of each wire. Any value above 1 ohm may indicate that the power cord is starting to fail and may overheat while in use. If any wire shows high resistance or "OL" is displayed on the meter, replace the entire power cord.
3. View current draws – premium users
Sometimes low or high current draw indicates a problem with the motor. It can alert you on how to fix electrical problems when the system is not functioning properly. Current draw is measured by using a clamp accessory connected to a multimeter or using a clamp meter. If you don't know what this looks like, check out our Amprobe clamp meter review.
For current measurements, connect the clamp meter accessory or grab the clamp meter. The accessory connects to the current jack and the common jack of the multimeter. Clamp the jaws around one conductor (wire) of the circuit to be measured. Often, you'll find the power cord splitting off the appliance side, but if you don't fully understand the risks here, be careful or hire an electrician. Be careful not to pinch the jaws of the two wires, this will cancel the signal, showing zero current.
Tech Note: The current clamp acts as a step-down transformer, taking the higher current drawn by the appliance and converting it to a much smaller current (typically 1000 to 1) that the DMM can handle.
To make current measurements with a clamp meter, select the AC current function and place the jaws around a conductor. The display will show the current being measured. What you're doing here is making sure the device is actually drawing current in the first place. A non-working device could simply be unable to draw any power because it has a problem elsewhere and is malfunctioning internally.
Check out the Klein Tools CL800 AC/DC Clamp Meter – Buy It Now ($129.97)
4. Check the switch
You can quickly troubleshoot electrical problems by checking the onboard switches on small appliances. Make sure power flows through them and to the correct destination. You can verify this in several ways. With the device plugged in, you can check the voltage at the input and output of the switch.
Plug the probe leads into the voltage and common inputs and set the meter to AC voltage (VAC) mode. Touch the black probe to ground (the metal frame of the unit) or to the neutral connector (white wire) on the power cord. Carefully touch the red probe to the connector on the switch, first one side, then the other. With the switch in the "ON" position, voltage should be present on both the input and output lugs.
Bonus Step: Check Continuity
Another way is to check for continuity through the switch. For this test, first remove power from the switch by unplugging the unit.
Next, isolate the switch by removing the wires from one side of the switch.
Then, with the multimeter set to the Continuity function, place one lead on the switch's input lug and the other on the switch's output lug. When the switch is turned on, the multimeter should emit an audible continuity signal and read approximately zero ohms. With the switch in the off position, the sound should stop and the meter will display "OL". If not, you've found a problem: a defective switch.
Solving electrical problems in home appliances can seem daunting. However, if the problem is just a loose cable or a bad switch, why pay hundreds of dollars for an easy fix? Many electrical problems can be easily and quickly resolved by a homeowner willing to spend a few minutes doing some basic troubleshooting.
Hope this guide is helpful to you – we love passing on tips from electrician professionals that may be helpful to other professionals not working in the field. If this helped you, or if you have other troubleshooting steps to suggest we add here, please leave a comment below!