Install the Car Stereo Wiring Harness
When you purchase an aftermarket head unit, you may don’t know how to connect the car stereo wiring harness as it is not the same as the original wire harness on your car. So there are several different ways to work this matter. If you have the factory wire harness, but there is no harness that came with the head unit when it was new, you can either purchase a wire adapter, or make one by yourself.
If all the factory wiring harnesses from your car had been cut before, then all you have to do is identify all wires and connect them one by one to your aftermarket head unit. In other words, if there is no wiring harness with the head unit, and the wires from the car are all exposed, that is a little bit complicated, but it can still be worked out
Wiring a Car Stereo With No Factory Harness
Although the car stereo wiring harness adapters allow for plug-and-play head unit installation, the most common way is to cut the factory harness and solder in the car stereo wiring harness during installation. There will be the bare wires if the head unit is disassembled in the future. Or if you just simply want to upgrade or replace to a new aftermarket head unit, you have to cut the harness of the car stereo out and start from the beginning.
When you see the messy wires in the car, you might find it complicated. But don't worry, it is an easy problem to solve. The easiest solution is to contact your car dealer and ask for the wiring diagram of your model, or search the Internet for diagrams that show which wires do what.
If you can find the colors corresponding to the speakers, power supply, ground, ACC, and any other wires, then all you have to do is to find them in the dashboard and connect them to the corresponding wires on your head unit.
If you can't find this information online, or you would rather use the old-fashioned way to figure out which line does what. You need to use some tools, like a test light, a multimeter, and perhaps a 1.5V battery, you can solve all the problems in a few minutes.
Wiring a Car Stereo With No Head Unit Harness
This situation is more complicated, and you may need to make some accessories yourself. If you can find a new or used harness, that would be the best. Unless a new harness is available, you can find a used one from a local wrecking or used parts export.
Get a diagram of your head unit. The best way to find this is to find the label corresponding to your model, and then search the Internet. Even if the manufacturer cannot provide enough information, you can find pinout information in forums or other places.
Fabricating a New Head Unit Wiring Harness
If you can find the pinout data, you can make the wiring harness based on these data. The best way to do this is to obtain something called a “rectangular connector” sized to fit your head unit.
In most cases, you will need a two-row rectangular header connector with female receptacles, which is a "through hole" mount type. In most cases, you need a two-row rectangular header connector with female receptacles, which is a "through hole" mounting type. This type of connector is usually designed to be mounted on a circuit board, but it is also used to replace car audio harnesses when necessary.
You may not find a car stereo connector with the correct pin spacing and the correct number of pins. Although the pin pitch is important, the number of pins is not important. You can use multiple smaller connectors or reduce a larger connector to adapt to see which one works best.