Do I need a Wiring Harness To Install An Aftermarket Radio

A wiring harness is one of the most needed parts when installing an aftermarket double din radio into a car.


Yes, you will need an aftermarket wiring harness to properly install your new radio. Nearly all aftermarket stereos are designed to be installed with an aftermarket wiring harness, which usually connects to the factory radio plug.

A wiring harness is used to connect the radio to the vehicle’s electrical system. It makes it easy to install an aftermarket radio without splicing any wires. It allows the connectivity of the radio to the factory adaptor of the vehicle easy and makes the aftermarket radio function normally.

Unfortunately, some vehicles, especially older models, may not have a factory plug for an aftermarket stereo. If this is the case with your vehicle, you will have to cut and splice the existing wires in your car. If you are installing a stereo without a factory plug and do not want to cut and splice, we recommend using a universal bypass harness.

A bypass harness allows you to use the factory amplifier by bypassing it and sending the signal directly to the speakers. This is useful if you would like to use your factory amp but do not want to cut it into your wiring.

Harnesses connect aftermarket radio to the factory adaptor point of a car, where each wire is directed to its sourcing point or control point.

In this article, I will expose the reason why you need a wiring harness for the installation of an aftermarket radio and explain some subordinate information related to wiring harnesses.

How do you Hook up a Car Stereo Without a Harness?

There are a couple of ways to solve the problem, depending on what you mean by “wiring a car radio without a harness.” If you have the factory harness but not the one that came with your head unit when it was new, you can either purchase an adapter or make one yourself if one is available.

If you have everything that came with the head unit but the factory harness was cut out of the automobile at some point, all you have to do now is identify the wires and solder them into your head unit. However, when your head unit doesn’t have a harness, and you’re dealing with bare wires in your automobile, it’s a more difficult but still manageable project.

Even though head unit harness adapters enable plug-and-play head unit installation, it’s rather normal for installers to cut the factory harness and solder in the head unit harness during the installation. You’ll be left with naked wires if the head unit is removed later, or you’ll have to take out the aftermarket harness and start over if you wish to upgrade to a new aftermarket head unit.

While looking into your dash and seeing a tangle of cables may appear intimidating, this issue is extremely simple to resolve. The best answer is to obtain a wiring diagram for your specific vehicle’s make and model or to search online for a diagram or table that explains which wires perform what.

If you know the colors of the speaker, power, ground, memory stay alive, and other cables, all you have to do now is find them on the dash and connect them to the appropriate wires on your head unit.

If you like to do things the old-fashioned way, determining which cables control functions is a simple procedure. You can get everything sorted out in a few minutes with a few basic instruments like a test light, voltmeter, and possibly a 1.5V battery.

how to install a radio with a wiring harness adapter

Installing a radio with a wiring harness is crucial, and it takes high sensitivity to understand the process. Because of this, I explained how to install a radio with a wiring harness adapter easily without looking for another guide.

The installation process that is about to be explained in this section of the post applies to the installation of a new wiring harness or aftermarket radio into a car.

To easily install a radio, the first thing you need to do is to connect the new wiring harness adaptor to the factory radio harness. After the connection, you can now connect the end part of the wiring harness into the port at the back of the radio then the radio will start working correctly.

Colors Code for Car Stereo Wiring Harness

Identifying the OEM wires using diagrams for the exact vehicle and the head unit is the simplest approach to wiring an aftermarket car radio. Despite this, the job can be completed without the need for labels, adapters, or diagrams. Unlike OEM head units, which have a wide range of wire colors, most aftermarket manufacturers stick to a consistent color scheme.

Although there are exceptions to every rule, the power, ground, antenna, and speaker wires on most aftermarket car stereos follow a standardized color scheme. Assume you have the standard-color pigtail that came with your aftermarket head unit. In that situation, the wires’ functions and colors are as follows:

Power Wires

  • Constant 12V / Memory Keep Alive: Yellow
  • Accessory: Red
  • Dimmer/illumination: Orange with a white stripe

Ground Wires

  • Ground: black


  • Right front speaker(+): Gray
  • Right front speaker(-): Gray with a black stripe
  • Left front speaker(+): White
  • Left front speaker(-): White with a black stripe
  • Right rear speaker(+): Purple
  • Right rear speaker(-): Purple with a black stripe
  • Left rear speaker(+): Green
  • Left rear speaker(-): Green with a black stripe

Amplifier and Antenna Wires

  • Antenna: Blue
  • Amplifier remote: Blue with a white stripe

Are car stereo wiring harnesses universal?

Car stereo wiring harnesses are universal and they can be used according to the features car owners want. But in some cases, if you are willing to install a screen touch into your dash din, the wiring harness might be different and the installation process might end up being technical.

How much does it cost to install a wiring harness?

The installation price for installing a wiring harness varies but it normally ranges from $39 – $135. Although the cost varies according to the length of the wire, quality, and durability of the product, sometimes the place you are buying it might determine the price you are going to spend.

How do you rewire a car wiring harness?

To rewire a car wiring harness, there are certain steps you need to take and things you need: knowing the color code and its right position, preparation of a tape to protect it from electric shock, and a blade to peel the mouth of the wire for safe connection.

Below is the process to rewire a car wiring harness:

  1. Follow and arrange the color code of the wire
  2. Peal the wire to easily connect it
  3. Connect the wire according to the color code and use tape to bind it.
  4. After this, you can now install and test if it is perfectly connected.

What is the Importance of a Wiring Harness adapter?

The importance of a wiring harness adapter is to make the connection between an aftermarket radio to the factory wiring harness and make it receive current from the car electrical part so that it could function according to the way it was programmed.

In conclusion, a wiring harness is very important when doing anything related to radio in a car, because it is what determines if the installation will be successful or not. At the end of this module, I am confidently sure you must have learned one or two things about the wiring harness, its color code, how to install it, and more. If you have a question, do not hesitate to use the comment box below.


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