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Why Is My Car Amp Not Getting Power?

Car amplifiers are essential if you want to enjoy quality music and increase the bass in your car’s sound system.

For an amplifier to be effective and provide quality sound, it needs power from the external source, but why do car amplifiers may not get any power? Let’s find out.

Generally, if the car amplifier does not get any power, it may be due to one of the following issues:

  • Disconnected, broken, or shorted power wire
  • Broken, shorted, or disconnected remote wire
  • Missing, corroded, or loose amplifier ground wire
  • Blown fuse.
  • Dead or low car battery
  • Loose or corroded car battery cables
  • Faulty alternator
  • Insufficient voltage to the amplifier
  • Stereo or car is not turned on
  • The amplifier is in protection mode

As an Amazon Associate, ImproveCarAudio will receive a small commission from qualifying purchases made through the links in this article.

Tip: For the amplifier connections, there is not only the size (gauge) of the wires important but also their quality.

I have been using Knukonceptz OFC wires and can recommend them to anyone. Especially if you run the cables through the tight corners, Knukonceptz wires are flexible and easy to install.

In this article, I will explain some of the most common reasons why your car amplifier is not getting power and how to fix each in the fastest way.

Why the Car Amp Is Not Getting Power

We have all been there. You are driving, listening to your favorite music when the power suddenly dies, and the music cuts out.

If your amplifier has a power and protection light, check what color it has illuminated:

  • If it’s red, your amp has shut down due to excessive heat, a short circuit, or other electrical problem.
  • If it’s yellow, that indicates a low-impedance situation — usually too low of an ohm load.
  • If there is no light on your amp, your amp is not getting power at all.
car amplifier in protection mode

If your car amplifier is not getting power, it will not work, and surely, you don’t want that.

First things first, you need to figure out why isn’t it getting power in the first place. The most common reasons for your amp not getting power include the following:

  • There may be a blown-up fuse that needs replacement.
  • The amplifier’s power wire might be touching or shorting against the metal.
  • You might have an undersized fuse that isn’t allowing the correct amount of current flow.
  • The ground wire of the amplifier is not connected correctly or might be loose or corroded, resulting in no power to the amp.
  • There may be a loose connection somewhere in your system.
  • Dirty Battery Terminals that need cleaning up
  • Your car battery is dead, and you did not charge it.
  • The amplifier might be in the protection mode due to excessive heat.
  • Maybe you forgot to turn on your stereo or car.
  • You may have a faulty alternator.

Blown Fuses

Blown fuses are the most likely cause behind an amplifier not getting any power, and you should always check your fuses before starting anything else.

If your fuse is blown, replace it with one of the same values.

Never use a fuse with a different than original amperage. This can cause entirely damage to your amplifier or car.

Most of the fuses in the car, including the radio fuse, are located behind the removable plastic panel on the driver’s side of the dash. The plastic panel can be removed easily by hand with slight pressure and pulling it down.

blown car audio fuse

After removing the plastic panel, you will see all fuses in your car, including stereo fuses, dome light fuse, cigarette lighter fuse, etc. however, the fuse in the amplifier is located directly on the amplifier, not on the main fuse box.

Regardless of where you take the fuse out, there are two ways to know that it has blown.

  • First, you can take out the old one and look at the metal filament inside the fuse. If it seems broken or burnt, you will have to replace it.
  • Second, if you do not want to remove the fuse or think it is okay, you can use a multimeter to check whether it is working.

Disconnected, Loose, or Broken Power Wire

If your amplifier is not getting power, check that both ends of your power wire are securely connected to the battery, fuse, and amplifier terminals.

If you find any problems with the power wire connection, fix them by reattaching or replacing the loose or damaged wires.

wrong car amplifier connection

If you suspect that your amp might not be getting power from its electrical source or want to know whether it is getting too much power, you can verify that your amplifier is receiving power by checking its voltage with a multimeter:

  • Use a multimeter to measure resistance between the positive and negative leads on your amp’s power supply; anything outside this range indicates extra voltage.
  • Use a multimeter to measure AC voltage between the positive and negative leads on your amp’s power supply.

Shorted or Disconnected Remote Turn-on Wire

In this case, your remote turn-on wire has come into contact with a positive wire, or there is an electrical short somewhere in your system.

Ensure the remote turn-on wire is connected to the receiver’s remote output or switched accessory wire. Otherwise, the voltage will not flow through it, and as a result, your amplifier won’t get any power.

If you are not comfortable checking the wires by yourself, you should take your vehicle to an electrician or professional car audio installer who will be able to check and make sure the wiring is correct.

Faulty Alternator

If your car amplifier is not getting power, this could be due to a fault in the alternator.

The alternator supplies the battery with electricity when the engine is on to provide power to various car components. Therefore, a faulty or damaged alternator can cause your amplifier to not receive power.

In addition to the lack of power for the amplifier, a faulty alternator can also cause other electrical components of your car not to work, such as the headlights or turn signals.

If there is a problem with the alternator, in most cases, it will require a replacement with the new one.

damaged car alternator

Low Or Dead Car Battery

Sometimes, a low or dead car battery is one of the reasons why your car amplifier is not getting power, especially if you listen to music with the engine turned off.

If your car battery is dead or dying, it will not be able to send an adequate amount of power to the amplifier, and therefore, the amplifier will not work.

You can check for a low battery by turning the key to the “on” position. If it does not turn over, then you need to recharge it.

Also, you can check for a low battery by turning on all the electronics in your car (radio, headlights, A/C, etc.). If the lights seem dim or flicker, the battery is flat.

Another way to check the battery is to use a multimeter.

  • If it reads 12.4 volts, then your battery is fully charged.
  • If it’s below 12.4 volts, your battery may need to be recharged or, in some cases, replaced.
  • If your battery gives less than 12 volts of electrical power, you can face the “no power” issue in your amplifier and other car’s electrical components.

Loose Cable Connections

Before you take any step, check all the cable connections and make sure that none of the cables is loose because a loose connection can cause the power supply to stop from reaching the amplifier.

You need to ensure that both the remote wire from your stereo and the power wire from your amp wiring kit is connected to a constant 12-volt source in your vehicle.

Once you have done this, check to see if your amp turns on.

You can use either a switched or an unswitched source, but if you have a stable amplifier connection with the battery, make sure there is an inline fuse on the power wire installed within 18 inches of the battery’s positive terminal.

If neither the remote wire nor the power wire is connected correctly, it will look like your amp isn’t getting any power because it won’t turn on. 

Faulty Power Connections

Before doing any wiring investigation, disconnect the ground power wire from the battery.

To check if your amp is getting power, you need to know how to read a voltmeter and be able to use a multimeter device to test the voltage at the amplifier.

Testing for power at the amplifier may require opening up the trunk or back of your vehicle.

Once you have access, you can use a multimeter to find out if there is any electricity flowing through your car amp, and to do this, check right, follow the few steps below:

  • Unplug the remote turn-on wire from the amplifier.
  • Turn on your vehicle and turn up the volume.
  • Using a voltmeter and setting it to DC 20V, touch each end of one of the speaker wires with the multimeter leads. If the voltage measurement on the screen shows less than 10 volts, then there is no electricity traveling through those wires, which means there is no power going through your amplifier either.

Stereo or Car Not Turned On

If you have not turned on your stereo or car, the amp can not get power, especially for the newer cars.

Most of the OEM amplifiers connect to either ignition or accessory switch so that you can turn it on and off from your stereo controls or a switch inside your vehicle.

You should connect the car amplifier to the stereo via the remote wire. This means that no matter what, your amp will get turned on once you turn on your car radio.

Bad Ground Connection

Sometimes grounding wires can become corroded or lose contact with their intended ground source. 

The amplifier must have a secure ground connection. Otherwise, the amp will not work correctly. 

To fix this problem, disconnect the ground wire from the car chassis, strip about ½ inch of the insulation off the wire, clean up the area where you plan on cementing with sandpaper or steel wool and then reattach it by screwing it down tightly to the chassis.

Ensure the ground wire is connected to the bare car chassis, not to any painted area.

Loose Or Corroded Car Battery Cables

Another common reason your car amplifier isn’t getting power could be loose or corroded car battery cables.

The first thing you need to do after turning off the ignition is to check the tightness of your battery terminals and cables.

corroded battery terminals

If they are loose, tighten the connections and see if it works. You will have to clean or completely replace them if they are corroded.

Amplifier In Protection Mode

Amplifiers have a protection mode that is designed to protect them from damage that can be caused by excessive heat.

Car amplifier protection mode will shut down an amplifier when the internal temperature reaches a predetermined point and will not turn on again until the temperature drops.

If the amplifier is overheating and going into protection mode, you need to fix the problem as soon as possible. If you do not make repairs, you risk burning out your amplifier or system components.

Conclusion

Most of the time, people tend to blame their car amplifiers for not getting power. But that is not always the case, and often the real problem lies with the connection or quality of the wires used.

Regardless of the case, when the amplifier does not seem to receive any power, you have to investigate each possibility not only to keep the amp working but also to make sure the electrical system in the car is in good condition.