How to Trace a Wire with a Multimeter (3-Step Guide)

If you haven’t got a proper grasp on how to trace a wire with a multimeter, this post will definitely give you some good tips. It could be a home electrical wiring project or tracing a wire on your car; whatever the situation, without proper technique and execution, you might get lost. 

With a simple continuity test, we can easily trace wires in a home electrical system or your car’s circuit. For this process, we will need a digital multimeter. Use the multimeter to detect the continuity of the particular circuit.

What is a Continuity Test?

Here is a simple explanation for those who are not familiar with the terms of continuity in electricity.

Continuity represents a complete path of current flow. In other words, with a continuity test, we can check if the particular circuit is closed or open. A circuit that remains in the ON position has continuity, which means the electricity flows through that circuit in a complete path.

Using continuity tests has many advantages. Here are some of them.

  • Can check the condition of the fuse; good or blown.
  • Can check the switches are working or not
  • Capable of checking conductors; open or shorted
  • Can Check the circuit path; clear or not

In this post, we will use the continuity test to check the circuit path. Then we can easily trace the wires.

How to Set the Multimeter for a Continuity Test?

multimeter circuit diagram

First, set the multimeter for the ohms(Ω) setting. Turn on the audible alarm. If you follow the steps correctly, the screen will display OL. Now your multimeter is ready for a continuity test.

Tip: OL stands for open loop. If the testing circuit has continuity, the multimeter will display a reading above zero. Otherwise, it will display OL.

Aim of the Continuity Test

Usually, your car includes plenty of circuits. With the help of proper electrical wiring, these circuits carry signals and power to each component of the car. However, these electric wires can get damaged over time because of accidents, misuse, and component failure. These kinds of failures can cause open circuits and short circuits.

Open Circuit: It is a circuit with broken continuity, and the current flow is zero. Usually displays a high resistance between two points.

Closed Circuit: There should not be any resistance in a closed circuit. Therefore, the current will flow easily.

We hope to identify the open circuit and closed-circuit situations using the continuity test with the following process.

How to Use a Continuity Test for Identify the Improper Wires in your Car

For this testing process, we will look at how to trace wires with a multimeter in a car. It can be pretty handy for identifying some severe issues in your vehicle.

Necessary Tools to trace Wires in a Circuit

  • Digital Multimeter
  • Wrench
  • Small mirror
  • Flashlight

Before starting the process, gathering all the above tools is a must. Now follow these steps correctly to trace the wires.

Step 1 – Disconnect the Power

First, disconnect the power from the testing section of your car. You should not ignore this step, and the best way to do this is to remove the battery cable. Use the wrench to remove the battery cable. Furthermore, disconnect the particular electrical device that you plan to run the test from the voltage supply source.

Step 2 – Inspect All the Connections

First, identify the electrical wires you need to check in this process. Make sure all of these wires are reachable so, you can check them with a multimeter without any trouble. Besides, pull those wires to check the strength of the connection points. Afterward, check the length of the wires that you are testing. Also, check for any damaged wires too.

However, sometimes, you might not be able to reach every point. Therefore, use the small mirror and the flashlight to reach those positions. Also, you might spot some black spots on the insulation; it could be a sign of overheating. If that is the case, the wires that work with the insulation might be damaged. (1)

Step 3 – Tracing

After checking everything, now you can trace the wires. Locate the wire connector and remove it for better inspection. Now you can examine the damaged wires clearly. Then set the multimeter for a continuity test.

Now place one of the multimeter’s leads on the metal terminal that attaches the wires to the connector.

multimeter tracing or testing process

Then place the other lead on any part of the wire. Shake the wire if you need to identify improper connections. If you follow the process correctly, now you will have one lead on the metal terminal and the other on the wire.

The multimeter should give a reading of zero. However, if it shows some kind of resistance, it is an open circuit. That means the particular wire is not working properly and needs to be replaced soon as possible. Also, apply the same method to the end of the wire. Do this for all remaining wires. Finally, observe the result and identify the broken wires.

How to Use a Continuity Test in Your Home?

If you need to trace wires during your home DIY project, it can be done easily. Follow these steps.

Tools Needed: A digital multimeter, a long wire, a few lever wire nuts

Step 1: Imagine that you want to check the connection from one outlet to another (consider points A and B). We cannot tell which wire is which exactly by looking at it. So, pull out the wires that you need to check. For instance, you will have to bring out point A and B wires.

Step 2: Connect the long wire to one of the outlet’s wires (point A). Use a lever wire nut to attach the wires. Then connect the other side of the long wire to the black lead of your multimeter.

Step 3: Now go to point B. There you can see lots of different wires. Set the multimeter for the continuity test. Then place the red lead on each of those wires. The wire that shows resistance on the multimeter during the test has a connection with point A. If other wires do not display any resistance, that means those wires do not have connections from point A to B.

Wrapping Up

Today, we discussed how to trace a wire with a multimeter in different situations. In both of these situations, we use a continuity test for tracing wires. We hope now you have a good understanding of how to trace wires with a multimeter in any environment. (2)

Below are other multimeter how-to guides that you can check and refer to for later use. Until our next article!






References
(1) mirror – https://www.infoplease.com/encyclopedia/science/
physics/concepts/mirror
(2) environment – https://www.britannica.com/science/environment

Video Reference

About Sam Orlovsky

b1d87d2ee85af3e51479df87928bdc88?s=90&d=mm&r=gI realized early on carpentry was a huge passion for me and I’ve stayed in the industry for over 20 years now. This gives me a unique ability to really be able to tell you what the best tools and recommendations are. I’m not only a carpenter but I also like machinery and anything to do with electrics. One of my career paths starting off was as an apprentice electrician so I also have a lot of experience with electrical products and anything related.