Blue and White Wire on Radio Harnesses: Standard Wiring Used In Stereo Installation

It can be challenging if it’s your first time installing an aftermarket stereo for your vehicle. You will ask yourself what the blue and white wire on radio harnesses does and how to perform the wiring successfully. Read on to learn about how to install an aftermarket stereo harness successfully.

What’s a Stereo Harness?

Harnesses act as adapters that allow you to install an aftermarket stereo with ease. 

You can use specialized harnesses to extend the wire or bypass the built-in amplifiers.

You can easily purchase stereo harnesses at affordable prices. To ensure you don’t encounter any issues, ensure that the wire harness you pick suits your vehicle and the aftermarket stereo.

Car Stereo

Car Stereo

Stereo Wiring Color Guide

Identifying the respective OEM wires via vehicle diagrams and head units will help you easily install your aftermarket car stereo.  

However, you can still get the job done without the help of diagrams because Most manufacturers use a standard color code for the speaker, ground, power, and antenna wires, unlike OEM head units that use a variety of colors.  

So, if you have the pigtail used in your aftermarket head unit, it will likely use the following color scheme.

How to Install an Aftermarket Stereo?

There are two ways to install an aftermarket stereo, using or not using harnesses. 

Install an Aftermarket Stereo Using Harness

First, you should choose the correct harness. There are countless wire harness adapter options for various cars and head unit combinations at affordable prices. However, the challenge comes in terms of compatibility. The head unit harness will only function properly if the design and a new head unit are specific to your car. After you figure out the model of the head unit you plan on installing, you can use several online resources that allow you to apply such information along with the model, make, and year of vehicle to find an available wiring harness adapter.

Then, keep the wiring diagram in mind. Often, people confuse the wire harness color to use for their car. Thankfully, harnesses typically use a standard color layout to help guide you. Otherwise, you’ll need a wiring diagram printed on the head unit’s exterior or available online.

Last, ensure you match the vehicle’s stereo wiring harness colors to the respective color slot on the wire harness. You will need to plug the opposite end of the harness into the vehicle’s head unit.

How to Install an Aftermarket Stereo Without Harness?

Usually, there’s a possibility you won’t find the correct harness for your car and stereo. Therefore, the only method to wire connections for your aftermarket radio is manual.

Before beginning any installation, keep in mind the vehicle’s color code. You’ll need to connect the cables coming out of the radio with a pigtail head unit.

If you have a used car stereo that you want to install and the pigtail that came with the head unit, check the list above to see to which each wire in the pigtail needs to connect.

Pigtail functions to connect the head unit to your model of car. However, failure to find the correct harness isn’t the end. You could still opt to directly connect the pins or use a pigtail to get the job done. While purchasing a pigtail, watch out for the color code it applies. 

Directly connecting the pins is challenging, and you should first acquire an idea of the diagram’s wiring because sometimes the color is different. 

Pigtail connector

Caption: Pigtail connector

Benefits of Using a Head Unit Harness Adapter 

As you can see, using a harness benefits a lot. Although aftermarket stereos have the same input and output design as the factory stereo in mind, often, the outputs and inputs aren’t in the exact position. Acquiring a suitable adapter makes the job easier. You must plug one of the adapter’s ends into the stereo and the other into the original harness connecting to the factory stereo.

Image of stereo connectors

Image of stereo connectors

Specialized Harnesses for Stereo

You can pick from many custom radio harnesses with stereo-wiring harness systems. 

Extension Harnesses

You often find that stereo connectors are pretty far from the stereo itself. In some cars, the stereo connectors are in the car’s trunk or near the fuse box. When you encounter such instances, you will need an extension harness.

Extensions provide longer extra wire capable of reaching any power terminals of the car. 

Blue and White Wire on Radio Harnesses: Amp Bypassing

In some cars, the stock radio system and amplifier are in different positions within the factory harness. Therefore, you can use an aftermarket car stereo with an amplifier.

You don’t always have to use the stock amplifier if your new aftermarket stereo has a better-inbuilt amplifier. Purchasing a specialized stereo harness allows you to look past your current stock amplifier.

Blue and White Wire on Radio Harnesses: Safety Alarm Retainer

All modern automobiles have an inbuilt safety alarm system. On some rare occasions, you will find that the safety alarm system is inbuilt into the factory stereo system. Therefore, you might eliminate the safety alarm system by replacing the factory radio system.

However, this doesn’t mean you can’t completely replace your stock stereo system. You have to get a specialized wire harness that functions to retain the safety alarm system even after replacing the stock stereo system.

Blue and White Wire on Radio Harnesses: Programmable Harness

Most modern vehicles have unique features built into the car’s stock stereo. Some of the features include Chrysler Uconnect and FORD Sync. In such cases, replacing the current stock stereo system means losing the fantastic additional features.

You will have to opt for a more advanced and expensive harness to avoid losing any additional features. Such harnesses allow you to program your harness and retain the unique features in your car.


There you have it; all you need to know is how to install your new aftermarket stereo. At Cloom Tech, we’re experts on all things harnesses, so if you need help, feel free to contact us

Hey, I am John, General manager of Cloom and OurPCB.

I am a responsible, intelligent and experienced business professional with an extensive background in the electronics industry.

Reach me at [email protected] to get a quote for your projects.


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