DIY Car Stereo Amplifier Installation Tips | AudioMotive

DIY Car Stereo Amplifier Installation Tips | AudioMotive

DIY Car Stereo Amplifier Installation Tips | AudioMotive

How to connect amp to car

A man with tattoos on his arm holds a crescent wrench as he stands in front of a display of car wheel rims.

the ultimate guide to car amplifier installation

If you like working on your car, you’re probably interested in upgrading your car stereo on your own.

This is a great opportunity to learn more about how your stereo works and how to get the best sound out of it. installing an amplifier and its accompanying speakers also allows you to develop some useful skills that you can use for future upgrades and tweaks.

While this job is tricky, if you’re confident in your cabling skills, go for it! And if you need a hand along the way, don’t hesitate to contact the car stereo specialists here at audiomotive.

ready to start?

what you will need

Car amps usually don’t come with wiring, so you’ll need to purchase wiring to connect your amp to your car’s stereo system.

power and ground wires

To supply power to your new amplifier, you will need to connect it to your vehicle’s electrical system with power and ground wires.

These cables must be thick enough to handle the power demand of the amplifier. a cable that isn’t thick enough could cause problems with your amplifier’s performance, or at least prevent it from putting out its rated power.

Consult your amplifier’s instructions to determine the recommended wire size to use. Wire size is measured in diameters, usually referred to as gauge. the lower the gauge number, the thicker the cable you will get.

Take the time to measure the distance between the car battery and the amp so you can get the correct length of cables.

a fuse in line

an in-line fuse on the main power cable, within a half foot of the connection to the battery, is a must. This fuse protects you, your car, and your stereo system from a short circuit that could cause a fire.

A typical 16 to 20 foot fuse is safe using one of the following:

Alternatively, look for amp wiring kits that match your amp’s specifications. amplifier wiring kits include fuses and corresponding power, ground, and ignition wires in one convenient package to help eliminate any potential confusion or damage.

rca cables and speaker cables

Amplifiers generally require rca cables to get input signals from the stereo receiver’s output. rca cables come in stereo pairs and in a variety of lengths.

When running speaker wires from your amplifier output to the speakers, you can use any size wire from 18 to 14 gauge. For subwoofers, use 16 to 12 gauge wire.

your step by step guide

Once you have all the components and wiring ready to go, it’s time to get to work!

note: Installation specifications depend on the amplifier equipment you have purchased and the make of your vehicle. when in doubt, call the professionals!

step 1: disconnect the car battery

Your car must be parked on a flat surface with the parking brake on. From here, open the hood and disconnect the battery, starting with the negative terminal. this will help prevent short circuits and electrical shocks while setting up your amp!

step 2: mount the amplifier

Choose a safe location to safely mount your amplifier. the manufacturer will usually include some recommendations in the included instructions.

As a general rule of thumb, amplifiers produce a lot of heat, so they need a few inches of air space on all sides to help keep them cool. don’t mount the amp upside down! while you may be able to save space, the heat it gives off will radiate back into the amp, causing it to overheat and creating a fire hazard.

You should also make sure there is enough space to connect the wiring and adjust the controls. But that is not all! your amp should also be at least three feet from your stereo to avoid interference and radiant noise. bolting the amp directly to your car’s metal chassis is also an invitation for noise issues. use rubber grommets around the mounting screws or mount to a wooden board before attaching to your car body.

Possible locations to mount your amplifier include:

Note that you will need to hide the wiring for security and appearance reasons. Depending on the location you choose, you will need to route the wiring under the dash, underside panel, door kickplate, or pillar trim panel. these panels can usually be removed by unscrewing and/or prying the edges.

Use zip ties to secure the wiring, especially if it’s behind the dash, to ensure the wires don’t interfere with any moving parts of the vehicle.

step 3: install the power cable

You will need to route the power cable from the car battery, through the car firewall, and through the car body to the amplifier.

To do this, find an unused grommet on the firewall to run the cable through. alternatively, you can find one with cables to pass through and enough space for the power cable to pass through as well.

If there are no existing grommets to use, drill a hole through the firewall, checking both sides to make sure you don’t puncture electrical wires or gas lines. use a grommet in the new hole to avoid damaging the cable passing through the hole.

step 4 – install the fuse holder

If your power cord already has a fuse holder installed, you can skip this step.

if not, that’s fine. Find a place to install the fuse holder near the car battery, ideally within 6 inches of the battery. anchor the bracket with a screw or cable tie.

Cut a short piece off the end of the power cable. this piece should be long enough to reach the car battery fuse holder. use a wire stripper to strip the insulation from both ends of the newly cut piece of wire.

Take a ring terminal from your wiring kit and thread it onto one end of this small piece of wire. put the fuse holder on the other end.

strip the insulation from the end of the power cable and connect it to the other end of the fuse holder.

step 5: connect the power cable

connect the power cable to the positive terminal of the battery.

For a top mounted battery post, crimp a ring terminal onto the end of the power cable if it is not already connected. remove the nut from the battery terminal, place the power cable ring over the bolt that holds the battery terminal to the battery post. then replace the nut.

terminal adapters are available for vehicles with side mount battery posts.

Run a wire loom over the power cord until it reaches the firewall and cut to length. then thread the cable through the short cable connected to the fuse holder and the battery.

step 6: install the ground wire

Look for a bolt in the metal frame of your car near the amp. if you can’t find one, drill a hole for one, making sure you don’t puncture any wires, lines, or gas tanks.

Crimp a ring terminal to the short ground wire. Scrape paint and clean debris from the bolt location so that the ground wire connection is bare metal. then firmly screw the terminal to the metal chassis of the car.

Loose or incorrect grounding is the number one cause of amplifier problems in car stereos.

step 7 – connect the rca, speaker and remote turn on cables

Connect these amp cables to the back of your stereo head unit. If your head unit does not have a remote turn-on output, you will need to connect the turn-on wire to the fused output terminal of the power cord.

connect the amplifier’s front, rear and subwoofer speaker cables to the corresponding speakers.

once all cables are connected, check that all wiring is tight and secure.

step 8: turn it on

sets all amplifier gains to minimum and disables all filters, bass boost, and equalization. make sure the main fuse is secure. and reconnect the negative cable of your car’s battery.

Turn on your vehicle and the radio. check the amplifier power light. turn up the music volume and check that the sound is coming from each speaker.

Test the stereo system using the balance, fade and subwoofer settings on the main unit. check that each speaker works without static or distortion.

sets the gain of the amplifier to match the input level of the amplifier with the output level of the receiver.

if all sounds good, reinstall the stereo and panels.


Common problems that occur with DIY car amp installations include:

To quickly fix these issues, or avoid them altogether, get expert help.

Visit car amp installation specialists for professional, worry-free car stereo installations and upgrades.

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