How to Install a Car Amplifier

How to install a car amplifier

Learning how to install a amplifier in your car is easy. All you need is the the proper supplies, a couple of hours, and the willingness to pull off some panels from your car. Once you have all of that, follow the steps below to begin installing your new amplifier!


Confirm all your gear is compatible

Before you even think about installing your new amplifier, it is important to make sure that your gear is compatible.
Car Amplifier – Will it phonically fit in your car? How are you going to run signal to the amp from the car stereo?
Power / Ground cable – Is it the recommended gauge for the amplifier?

Do you have the right wire?

You will want to make sure that your amplifier installation kit includes the right sized power and ground cable. A general rule of thumb is the following:

Wattage of all amps Recommended Wire Gauge
up to 400 watts 8 AWG
400 to 1000 watts 4 AWG
1000+ watts 0/1 AWG


Mount the Amplifier

This is important because the location of your amplifier will determine how long your runs of wire are. Typical locations for an amplifier are under seats, in the trunk, or even mounted to the subwoofer box. However you mount the amplifier, make sure that it is secured to the car. Most amplifiers will come with mounting directions. For most installations where you are putting the amp on carpet, you can slide a piece of MDF under the carpet to screw the amp into.


Run Power and Ground wire

The first set of wires you will run is the power and ground. This will provide the power to turn on your amplifier and ensure proper grounding. The power cable (positive) is run from the positive terminal of your car battery to the positive input terminal on the car amplifier. Your ground cable (negative) is run from the negative terminal on the amplifier to a grounding point on the vehicle. A proper grounding point will ideally be joined to the chassis of the vehicle.


Give the Amplifier signal

Once the amplifier has power, you will need to give it signal and tell the amp when to turn on. From the back of aftermarket car stereo, connect the RCA interconnect cables and then run them to amp. It is highly recommended that you run the RCA cables along the opposite side from which you ran the power cable. This will prevent any noise or interference that can transit from the power cable into the RCA signal. Once the RCAs have been run to the amplifier, plug them into the appropriate RCA input.

Next, run the remote turn-on wire from the car stereo to the amplifier. This is the small 16 gauge wire that cam in your amp kit. It will need to be connected to the remote turn-on wire from the wire harness on the back of the stereo. Run this wire with the RCA cables and insert it in the remote turn on input terminal on the amplifier. This will tell the amplifier to turn on when the car stereo turns on.


Connect amplifier to speaker or subwoofer

Now that the amplifier is powered and is receiving signal from the car stereo, it is time to send that signal to the loudspeakers. Run the speaker wire from the amp terminals to the terminals on the speakers or subwoofer. As a general rule of thumb, I recommend using 12 AWG wire for subwoofers and 16 AWG wire for speakers.

If you are connecting subwoofers, double check the wiring configuration to make sure that the impedance between the sub and amp match.


Test Everything

At this point you should everything connected and wired properly. Turn the car on and play a track on the stereo. You should be able to hear sound coming from the loudspeaker connected to the amplifier. If you don’t hear anything, you will have to trouble shoot the installation and find out whats wrong. If it is playing music, then you can turn the car off and put everything back together.

That’s it! If you can install an amplifier in your car, then you can install pretty much any other type of aftermarket car audio gear.

Pro tips!

    For first time installers, disconnect the negative batter terminal to prevent any electrical issues before or after the installation.

  • Dry fit everything before mounting the amplifier. This is ensure that the amplifier will fit and the wires are long enough.
  • Tune your amplifier! Once you confirm that the amplifier is functioning properly, spend some time tuning the amp to make it sound better.

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