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How to Find Ignition Wire for Stereo?

If you a car mechanic, it is essential for you to understand the functions and purposes of every cable in your car. But If you are new in this line, then it is hard for you to find a particular wire for your car stereo. Well, here in this article, I share some knowledge about how to find ignition wire for stereo in a car.

By doing this, you will also be able to learn the other wire functions and purposes also. So don’t be late and let’s get started.It’s a straightforward process on to find ignition wire for double din stereo / touch screen in a car.

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Double Din Car Stereo with Backup Camera
7 inch Double Din Digital Media Car Stereo
Regetek Single Din Car Stereo
Car Stereo in-Dash Single DIN
A-SURE Android 10.0 2GB+32GB Dual-Tuner Android Auto+Carplay Bluetooth 5.0 DSP Car Stereo


There are two ways to find the radio ignition wire in the car. The first one is your vehicle’s radio diagram, where you can locate the radio ignition wire.  By this radio ignition wire diagram, you can find the exact make, model, and year of your radio ignition wire.

Once you find the diagram of radio ignition wire, then you have to read it and understand it. Later try to match up the picture of your radio diagram and what you can see in your car stereo. It’s that simple. However, coming across a chart may not be that easy.

Luckily for you, without having a diagram, there is another way to locate the ignition wire in a vehicle. It’s effortless and pretty much accepted for all. At first, it may be different for you to understand because there aredifferent colors of wires in a car stereo. But after reading this guideline, it’s become easy for you and you can easily findignition wire for your car stereo.

Required Tools

To find ignition wire for stereo you need a multimeter or test lamp. At first, you have to remove the radio from the dash board. So that you can see all the different wires of your car stereo. Then connect the multimeter with the clamp for testing.

After that, it’s time for testing wires.

Test The Wires

Most radios have different colors of wires. Before installing a car stereo, first, you have to understand the functions and purposes of different cables.

In your car stereo, you may see red, yellow, and black wires. These are called power wires. Power wires are mainly responsible for powering up your car stereo.

The yellow wire helps to keep the battery stable, and it has constant power. Your car stereo will not work if the black wire is absent and also known as ground cable. The red wire is the important one, and it is the ignition wire. To make sure you have to test the wires because there are two red wires. One is the ignition wire, and the other is the dimmer wire. The red wire also helps to turn the radio on and off.

First, you have to check the constant 12V wire power. To check constant 12V wire first, you have to set your multimeter to the appropriate scale and without switch off the car, touch each wire with the probe. When the multimeter shows the approximately 12V, then you have found the constant 12V wire power. In Most stereo, a constant wire is yellow color and also known as the memory wire.

After finding constant wire now have to find the ignition wire. To see this, you have started the car and also have to turn on the ignition switch, headlights, and dimmer switch. Touch each wire with the probe. If you find two more wires that show approximately 12V, then turn the dimmer switch down and check again. The cable that shows less than 12V at that point is the dimmer or illumination wire. The wire that still shows 12V is the ignition wire, which is usually red. Label them, so you don’t lose them.

Once you have identified the ignition wire, the ground wire, the constant power wire, and the dimmer wire, then you see that there are some others wires. The last bunch of cables is for speakers of your car stereo. They have come in pairs, so it is very easy to differentiate. The ones without stripes are for positive wires, and the other ones with stripes are for negative wires.

  • White ones: For front left speakers
  • Gray ones: For front right speakers
  • Green ones: For rear left speakers
  • Purple ones: For rear right speakers


And that’s it. In this way, you can easily find your ignition wire for stereo. But by using a multimeter is an easy way than locating a diagram. And it is also a guaranteed method to work.

One thing you have to remember that, most radios have different colors of wires and the red one is usually the ignition wire. But to make sure 100 percent it a good idea to test the cable with the multimeter.

If there are any other suggestions or questions about how to wire a car stereo without a harness, just let us inform. Also, all ideas will be much appreciated!

Angela E. Bouchard
Angela E. Bouchard

Angela E. Bouchard is a writer and blogger as well as the chief editor of Route Vibes. She was grown up in a small neighborhood of Linden Avenue, Orlando, FL. From childhood, she has developed a keen interest to know about everything. Such characteristic helped her to become a passionate writer as she grows up. Before starting at the Route Vibes project, Angela E. Bouchard worked as writer and editor at multiple top-notch blogs and magazines. You can follow her on different social media, including Twitter, Instagram, Facebook, and Instagram, to know more about his work.

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One comment

  1. So I’m trying to figure out what I took the yellow constant wire coming from the stereo up to inside my car cuz I don’t see I do see another yellow wire but it’s stating that it’s something else on my diagram

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