How to Wire a Car Stereo

Co-authored by wikiHow Staff

Last Updated: December 3, 2022 References

Remove the Old Stereo

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Wire the New Stereo

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Install the New Stereo

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Q&A

Installing a new car stereo is a great way to breathe new life into your old daily driver. Adding a CD player or MP3 ready stereo to your car can give you the opportunity to listen to new music as well as improving the overall sound quality of your car’s sound system. Doing the installation yourself can be a bit daunting, so it’s important to approach it with patience. Because every car and every model stereo are a bit different, you might want to do some research on your specific car before getting started.

Part 1

Part 1 of 3:

Remove the Old Stereo

1
Disconnect the battery. Because you will be working on the electrical system of your car, it’s important to disconnect the battery before you get started. If you aren’t sure where to locate the battery in your vehicle, refer to your owner’s manual; most car batteries can be found under the hood, but some are kept in the trunk. Once you locate the battery, use a hand or socket wrench to loosen the black cable from the negative terminal on the battery. You will not need to remove the bolt entirely, instead simply loosen it enough to pull the cable off of the terminal. Tuck the cable down to the side of the battery so that it can’t come back into contact with the terminal.^{[1]
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- You do not need to remove the battery or disconnect the cable from the positive terminal.
- To be sure the battery is disconnected, check to see if the lights come on in the cabin of the car. Nothing electronic should work with the battery disconnected.
- Disconnecting the battery will prevent you from doing damage to the electrical system as well as protect you from shocks.
2
Remove any necessary pieces of trim. You will need to gain access to the sides of the stock head unit (or stereo) in your center console. In some cars, that will require the removal of some pieces of plastic trim. Be careful when removing trim pieces, as they may be brittle and subject to cracking. Whenever possible, try to pull the piece of trim out slightly to get a look at what kind of clip is used to attach it. You may need to slide the trim piece in a certain direction to separate it, you may need to hit a release with a screw driver, or you may need to simply pull on it hard enough. Checking first will prevent you from breaking off the clips and having to replace the piece of trim.^{[2]
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- Consult your car’s repair manual if you want to determine the best way to remove pieces of trim that are in your way.
- Set the trim aside where you won’t accidentally sit or step on it as you work.
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3
Determine how your head unit is mounted. Car stereos are all held in place using one of two methods: spring clips or bolts. Each method requires a different technique for removal. In order to determine what method your car uses to secure the stereo, you can consult your car’s repair manual or look closely once you’ve gotten the trim out of the way. Spring clip mounts may not require the removal of any trim pieces and can be identified by the matching pairs of holes on either side of the stereo. Stereos that are bolted into place may require more trim removal, as you will need to gain access to the space behind the stereo.^{[3]
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- Look for two pairs of matching holes on the left and ride side of the stereo. If they are present, your stereo is held in place with spring clips.
- If there are no holes, remove the trim below, above or to the side of the stereo to gain access to the bolts.
4
Use DIN tools to remove spring clipped stereos. If your stereo or head unit is held in place using spring clips, you will need to purchase a pair of DIN tools. DIN tools look like thin pieces of metal bent into the shape of the letter “U” with slightly hooked ends. Insert one DIN tool into the two holes on the left, and another into the two holes on the right. Press them both in until you hear the click of the spring releasing. Spread the tools apart slightly to grip the back of the stereo and pull the tools toward yourself. The stereo will slide out of the console of the car along with the tools.^{[4]
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- In a bind, you may be able to use pieces of a metal coat hanger to create your own DIN tools.
- If the stereo doesn’t come out, it is likely stuck by a piece of trim. Don’t force it out, instead look for any obstructions that may be preventing it from moving.
5
Remove a bolted in stereo with wrenches. You will likely need to remove quite a bit more of the trim to access bolts that hold your stereo in place than you would have with spring clipped stereos. Once you are able to see the bolts, removing the stereo should be fairly self-explanatory: there will likely be four bolts, either attaching the stereo to a bracket at the back or on either side. Determine the size of the bolts, then use a hand wrench to remove them. Some brackets won’t require that you remove the bolts completely, but may just need you to loosen them sufficiently to slide the stereo out.^{[5]
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- There may be a trim “faceplate” over the stereo that pops off, revealing bolts in the face of the stereo instead of behind it. Unscrew these bolts and slide the stereo out.
- Remember that the stereo is still connected to the car with wires, so be careful not to rip any out as you remove the stereo from the console.
6
Disconnect the wiring. If you are removing a stock head unit, there will likely be at least one plastic clip with a number of wires going into it that you will need to disconnect. There may be a second clip and an antennae cable as well in some cars. These few clips consolidate all the wiring required to connect the stereo to the car’s power source, the antennae and each of the speakers. If you are removing an aftermarket stereo, there is a possibility that there will be no clip and the previous stereo was wired loosely. If that is the case, you may have to cut the wires in order to connect them to the new head unit.^{[6]
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- Do not pull the wires out of the clip. If you are able to purchase a harness adaptor for your new stereo, it will plug directly into the car’s existing clip.
- Be careful when removing the wire harness clip from the back of the stereo. It may have a plastic button or tab holding it in place.

Part 2

Part 2 of 3:

Wire the New Stereo

1
Purchase a wiring adaptor. Your new stereo will come with a diagram indicating what each wire is and what it needs to be connected to, but that process can be made much simpler by using a wiring harness clip adaptor. These adaptors are made to make it easy to connect your new stereo to the car’s existing clip. Use the diagram provided with the stereo as well as the diagram provided with the clip, to loosely connect each of the wires to the new adaptor.^{[7]
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- You can order adaptors online or at most auto parts or electronics stores.
- Using the adaptor greatly reduces the chances that you will make a mistake wiring in your new stereo.
2
Identify and connect loose wiring. If you are not using a wiring harness clip adaptor, you will need to identify the wires coming out of the stereo, as well as those coming out of the car. Without an adaptor, you will need to cut the wires on the back of the car’s harness clip, but do so one at a time as you connect them to their corresponding wire on the stereo to prevent confusion. Use the repair manual for your car or locate a wiring diagram for your car online to aid in your efforts to identify each wire. Most car stereos will require the following connections:^{[8]
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- The power wire coming from the stereo is usually red, and likely will connect to a red wire from the car.
- The ground wire for the stereo will be black, as will its corresponding wire from the car. If there is no ground wire, you can secure the ground cable to bare metal in the body of the car to serve as a ground.
- The 12 volt constant power wire is usually yellow or blue, though it may be a number of colors coming from the car.
- The rest of the harness wires are for the speakers. Use the diagrams to properly match each with its appropriate wire from the car.
- The antenna wire is much thicker with a metal head and can be connected separately before you install the stereo. These wires are usually short and won’t be reconnected until you are about to install the new stereo.
3
Connect the output convertor if necessary. Some vehicles will require an output converter to make it work properly with components of the car that are not common industry wide. Some automakers use external amplifiers the stereo’s signal will need to compensate for. Your stereo may have come with an output convertor, but it’s more likely that you will need to order it from an auto parts or electronics store. Be sure you order an output converter designed specifically for your year, make and model vehicle.^{[9]
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- If you are unsure if your vehicle utilizes external amplifiers, refer to the owner’s manual.
4
Secure all connected wires. Once all of the wiring has been connected to their corresponding wires, you will need to make those connections permanent. There are a number of ways you can permanently bond two wires together and while some may be more resilient than others, most will work just fine for car stereo applications. Be sure there is no bare wire metal showing from any of the wire connections by wrapping them in electric tape or heat-shrink wrap.
- Soldering two wires together requires a soldering iron and solder. You melt the solder onto the wires to stick them together and as the solder cools it forms a permanent bond.
- Twisting wires together and then covering them with heat-shrink wrap or electric tape will suffice for car stereos.
- Connectors can be purchased that you simply slide both wires into and either crimp them together with pliers or twist them together with your fingers.

Part 3

Part 3 of 3:

Install the New Stereo

1
Test the stereo. Before you install the stereo in the center console of your vehicle, reconnect the battery and turn the car on to make sure it is functioning properly. With the stereo completely connected, turn it on and try a few functions. Make sure all speakers in your vehicle are working and that CDs or your MP3 player play properly. If you have been able to connect the antennae cable already, check to make sure the radio works.
- Checking the stereo’s functions now will prevent you from having to take the console apart again to address any issues with the wiring.
- If something does not work properly, review the connections with the wiring diagrams that you have to make sure all of the wires are connected to their corresponding match.
- Remove the keys and disconnect the battery again after you’ve tested the stereo.
2
Tuck all of the wiring into the dashboard. You may have noticed that most of the wires you connected to your stereo allowed for quite a bit of slack. Take the connected car stereo in one hand and use the other to tuck all of the extra wire back into the dashboard as you set the stereo in its opening. If you have not been able to connect the large antennae cable yet because it was too short, connect it now as you sit the stereo in its place.^{[10]
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- Be careful not to pull any wires out of the back of the stereo as you tuck them back into the dash board.
- Try not to let the wiring get in the way of the bracket you will need to bolt the stereo too (if your stereo requires being bolted into place).
3
Slide the stereo back into place. Slowly slide the radio back into the opening in the center console of the vehicle while being careful not to apply too much pressure to the face of it. If you encounter resistance, do not force the stereo in any further. Instead remove the stereo and identify what was in the way, move it, and attempt to slide the stereo in again. As you slide the stereo into place, wires may snag or plastic brackets may come out of place. Forcing the stereo past a snag can break things and make the stereo fail to function or seat properly in the vehicle.^{[11]
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- Some vehicles may require an adaptor to properly fit the new stereo in the hole for the old one. These adaptors can be ordered at auto parts and electronics stores.
4
Secure the new stereo. If your stereo utilizes spring clips, it will click as it locks in place and you will not need to take any further action to secure the stereo. If yours uses bolts and brackets, reuse the bolts you removed earlier to secure the new stereo in the same place. If you had to use an adaptor to properly fit the stereo in its space in the console, ensure the stereo is secured to the adaptor and that the adaptor is secured to the car.^{[12]
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- If you use bolts, make sure they are snugly tightened before reinstalling the trim.
- Once done, try to wiggle the stereo. It should hardly move at all when properly secured.
5
Reinstall the trim. Being careful not to break any of the plastic clips that hold the trim in place, reinstall each piece in the opposite order you removed them. That means you should install the last piece you removed first, followed by the second to last, and so on. This will make sure overlapping pieces are layered properly.^{[13]
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- If you break a clip and the trim won’t stay in place, you can use a hot glue gun to secure trim pieces to your car, but be aware that it will make it more difficult to remove those pieces again in the future.
- If you break an entire trim piece, you will likely need to special order a replacement from the dealership, as most auto parts stores don’t carry trim components.

Community Q&A

Question

Without the car harness clip, how can I tap the wires from inside when wiring a car stereo?

Moses Mk

Community Answer

You need to look for your car electrical manual. if the manual not available, you have no choice but to trace each wiring. A multimeter may come handy in this task. Head over to professional installer or a friends that may know about it. Car electrical systems can be nasty; never attempt without at least a basic knowledge.
Question

What is the key wire for?

Community Answer

The key wire is for transferring the electronic signals of turning the key fob to the battery, which turns on the rest of the engine.
Question

Why doesn't the unit turn off when the key is in the off position?

Community Answer

This likely because you didn't connect to the red ACC wire. That ACC wire is powered only when the key is in the ACC position. The main positive wire (usually a thicker yellow) is directly tapped to your battery. So it is important to connect to the correct wire.