How to connect car stereo wires? Stereo harness & Radio wiring harness

If loud, deep bass blaring music while you’re driving to the mall, school, work, etc., makes you happy, you’ve most likely considered changing the factory stereo that comes with your car.

Trust me, that’s not a bad idea. I’m with you on this one. You need a car radio system that is impressive and can announce to the entire neighbors on any street you drive through that it’s Friday night, and you and your friends are about to move the energy from zero to a hundred percent.

But you see, deciding to upgrade your car’s stereo system by changing the stereo is the easiest part. The most challenging part is changing the system. You might easily get confused trying to figure out how to connect car stereo wires, especially if you’ve never done it before, but you want to do it the DIY way.

Anyway, there’s nothing wrong with connecting the wires yourself. Just let us show you have to do it successfully. Now, grab a chair, sit down and pay rapt attention so you do not ruin the entire process.

Related: The Differences among Midbass vs. Midrange


How to connect car stereo wires without wire Harnesses

It’s not an entirely shocking or new phenomenon that some radio heads and cars unit come without the harness. Other times, your radio head could come with a wire harness. But the problem might be that it is not compatible with your car’s harness.

When this happens, do not get discouraged and think that you have to get another radio head or give up on having a sound stereo system. The reason is, you can still connect the car stereo wires and enjoy a sound radio system.

Yes, there’s a way to establish the connection without the wire harness, and we’ll show you how to do it. But first, you need to know the wires involved and their functions.

The reason, a harness adapter holds a mix of several color-coded wires. So, if you’re going to connect your stereo wires without harnesses successfully, you need to start by learning the necessary wires, especially if this is your first time trying this out.

  • The Blue Antenna Wire: this wire is responsible for controlling the antenna and signal of your radio. You’ll find two types of this blue wire. The first is the plain blue wire that’s responsible for the FM and AM radio frequencies. The other blue wire has white stripes, and it’s responsible for connections made to both the FM/ AM frequencies and connection to CDs, Media, and Bluetooth on the radio.
  • The Orange Wire: You’ll find two orange wires also. From their color, you can already guess what they do. As the sun with fiery orange color, these two orange cables are responsible for increasing and decreasing the brightness of your stereo.
  • The Power Wires: A combination of black, red, and yellow wires, they work to power on your radio unit. Nevertheless, all three wires have specific functions that they perform with regards to powering your radio. For starters, the stability of your car radio’s battery is all thanks to the yellow wire. The black wire keeps the radio functioning, while the red wire powers on/off the radio unit. These three wires work together in unison.
  • The Speaker Wires: these are wires in pairs and work for the stereo’s speaker. Since they come as a pair, they are generally split into two. For instance, the wire pairs that do not have stripes are the positive wires. The negative wires do not come with stripes. They are color-coded wires car stereos. The grey wires connect to the right speakers at the front, while the white wires connect to the left speakers. The right speakers at the rear are connected by the purple wires, while the green wires connect the left speakers at the back.

Related: Steps for measuring car speakers

Now that you know the wires and their colors and functions, let’s connect our stereo without wire harnesses.

Turn off the car engine:

Turning off the car engine is as easy as pulling out your key from the ignition. You’ll prevent certain accidents like electrocution from occurring.

Match the Color-coded Wires:

Now that you know the wires are color-coded, match the wires on your radio with the similar color-coded wires on the vehicle. However, if your stereo and car do not seem to have similar color-coded wires, refer to the manual to know the wires you’re joining together.

Secure the Wires:

it’s essential to hold the wires together after connecting them. You can do this via soldering or crimping. To solder two wires together, get rid of the insulation using a wire stripper. Then, melt the solder on the joined wires with the aid of a soldering iron. Leave it to cool off and watch as your wires would have been joined firmly to each other. To prevent accidents like getting electrocuted from occurring, insulate the connection via heat shrinking. To secure the wires via crimping, get a crimp connector of the right size to hold the wires together.

Mounting Kit:

Once you’ve successfully secured the wires together, follow the instruction manual on the best way to assemble the kit.

Related: Best DIY speaker kits

Reconnect the Power wires:

It’s time to reconnect the red, yellow, and black power wires.

Ground Connection:

This step is essential to keep the stereo’s sound quality in check. An easy way to make the ground connection is to establish a connection between the bare metal of your car and the ground wire of the radio.

Connect Loose Ends:

Do a thorough inspection of all the wires to ensure you’ve perfectly connected all the wires that need to be connected.

There you have it! How to connect a wire harness for car stereo in such a simple step process. Otherwise, you can easily buy a car wire harness, attach it, then use it to secure your stereo wires together.

Related: Best car audio setup for sound quality

Harness for a Car Stereo (Advantages of a wiring harness) 

Although connecting car stereo wires without harness wires is possible, there are a few benefits of establishing a connection between your stereo wires and your car with a harness.

After highlighting some of these benefits, you’ll probably prefer to buy a harness to connect your car stereo wires when the vehicle doesn’t come with one. Here are some of the advantages of a wiring harness.

  • Installation Time is shortened:If you followed the process of connecting your wires without the aid of a wiring harness, you should have an idea of what I mean. Although it’s possible to connect your wires without the assistance of a wire harness, it sure would consume a lot of time, especially for newbies. Then, you’ll have first to learn the meaning of each color-coded wire. Then, you’ll start to march them with the color-coded wires from your vehicle. Rather than individually connecting the wires, the wire harness does that for you. Hence, it reduces the time you’d spend trying to connect your car stereo wires.
  • Gets rid of wire clutters:If the sight of messy wires gets on your nerves, you seriously do not want to consider connecting your car stereo wires. The reason? The wires would look too cluttered up. But using a wire harness keeps the connection point decent and neat.
  • Prevents ugly occurrences:The wire harness firmly holds the wires together. As a result, the individual cables are protected from wear and tear, vibration, etc. If the wires stood without the harness, they’d be a lot more susceptible to the above-enlisted factors. There’s also the fact that a wire harness prevents the possible outbreak of fires in the car. It keeps the wires safely connect and out of the way of coming in contact with parts of the vehicle that could start an electrical fire. Let’s not forget that short-circuits aren’t likely to happen because of the insulating material used to create the harness.
  • High-Quality:Wire Harness comes fashioned with high-quality. Hence, you can trust that it would transfer solid power and signals to your radio unit readily. You won’t suffer from poor power signal transmission to your radio unit. The truth about harness wires is that the majority of the harness that you’ll come across are carved from high-quality materials. Hence, you can never go wrong with a regular harness as it would still deliver high-quality function.

Details guide on connecting car stereo wires with wire Harnesses

Now that you know the advantages of a wiring harness for car stereo installation and how much easier it makes connecting your stereo wires easier, we’ll show you how to connect stereo wires with it.

If your car stereo doesn’t have a wire harness, or your vehicle lacks or, or you cut the harness ruthlessly by mistake, don’t worry. It doesn’t mean you’re doomed to forever connect your stereo wires without a harness. You can purchase a solid wire harness, attach it, and you’re back on track.

The truth about wire harnesses is, there are different cars for the different harnesses. Hence, it’s not wise for you to blindly purchase a random wire harness off the market. You have to ensure that the car harness you are buying is the perfect fit for your car.

If not, you’ll probably need to return it till you get the fit for your car. Nevertheless, if you do not need to purchase a new wire harness, you don’t need to worry about shopping for one. Proceed with the following steps.

Know the Wires:

By now, you should already understand the color-coded wires and their functions. If you have no idea, refer to the section that dwells on connecting car stereo wires without a harness to refresh your memories.

Match the Harnesses together:

So, your car and your stereo come with functional harnesses? Good for you. It simplifies the entire connection process. Now, rather than try to match the individual color-coded wires of your car stereo with your vehicle, the harness presents a simple technique. Connect the radio’s harness to the car’s harness. Viola! You’ve connected your car stereo wire. If it’s your first time connecting harnesses, you should refer to your car and the stereo’s manual to know the best way to connect both harnesses.


After successfully connecting the wires via harnesses, secure the wires in place using either the soldering or crimping technique.

Mounting kits:

Proceed to assemble the mounting kits while following the manual.


With everything in place, you’re almost ready to use your stereo. Do a thorough check to be sure that you followed the instruction on the manual. Also, ensure that you test the stereo to e sure the wire connection is all good.


  • Can you connect stereo wires without harnesses? Yes, you can. However, it is a time-consuming process. Also, if you’re not a pro at connecting stereo wires together, you need to understand certain things first before you proceed to join the wires together. It’s both an easy and complicated process.
  • What is a Car Stereo Harness?A car stereo harness is that equipment that makes it easy for you to join and connect the necessary wires needed to transmit power or electrical signals to your stereo.
  • What is the best way to connect car stereo wires?The best way to connect car stereo wires is to use a stereo harness. It simplifies the connection process while preventing you from actually encountering the wires one-on-one.

Last words

With the wires connected adequately with or without a harness, you can now put your stereo in place. But be careful. When connecting the wire, ensure you test the audio quality of the stereo.

You do not want much of the audio quality lost in transit because you didn’t connect some wires properly. Nevertheless, if you follow the step-by-step process that we highlighted on connecting car stereo wires, you shouldn’t encounter problems with any wire.

Since your stereo wires are now held firmly together, fill the atmosphere with music or your favorite program while you go on any trip – bid farewell to boring trips.

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