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9 Reasons Why Your Car Stereo Wont Turn On But It Has Power

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Do you always go on long drives? You will certainly agree that driving becomes more enjoyable when accompanied by your favorite music tracks.

So, it is no surprise that you own a car stereo unit. It gives you energizing and soothing music while on the steering wheel.

However, if you turn on your car stereo but there is no power, the exciting road trip you imagined is suddenly ruined. What happened?

Is it the power wire or the ground wire? Keep reading to know why your car stereo wont turn on but it has power and what you can do to resolve this issue.

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9 Problems Why Your Car Stereo Won’t Turn On But It Has Power

If you notice a problem with any part where the electricity goes through or any power sources, your car radio will not work correctly. After all, no power, no music, and vice versa.

However, if your car stereo has power but won’t turn on, you may wonder what happened.

Wiring is one of the things your car radio malfunctions. Wires connect the car stereo to the power supply and speakers, usually placed beneath the vehicle’s dashboard. If there is a wiring issue, the stereo will not function.

Dead batteries, bad wiring, and blowing fuses that activate your car’s protection mode are some common problems it won’t turn on even if there is power.

You can quickly resolve it by checking the anti-theft protection mode, power at the head units, pigtail connectors, or fuses in the vehicle. Let’s take a closer look at the reasons your car radio won’t turn, but it has power.

Dead Car Battery

Your car stereo works very well most of the time. So, you will be surprised if your turn it on, but it does not work even if it has power. This may happen if your car battery is dead.

You will need to check the engine functions before knowing whether anything else in the car requires operational power. If you believe everything is in good condition, your car battery is in order.

If nothing else in the car needs power, you have to focus on the battery instead of the infotainment system.

Blown Fuse

Are you dealing with electrical issues? Then, always start by checking the stereo fuse box.

Blown fuses are easy to check, whether they are in the car stereo, headlights, or windshield wipers. Since fuse boxes have no standardized mounting place, you can easily find their location.

Fuses are usually found behind the head unit, protective cover, beneath the windshield, near the battery, or in the engine compartment.

You can also find them beneath the steering wheel, on the front cabin partition’s left corner, or underneath the center armrest.

Once you located the car fuse box, test if the fuses’ top metal spots are operational with a test bulb by tapping them. Alternatively, you can pull every fuse one at a time to know whether or not the metal wire that runs through the center has cracked.

It is best to replace a blown-out fuse with a new one. However, you have to ensure it is of the same rating. A whole spare fuse kit is inexpensive and includes a fuse plucker necessary for getting the built-in fuses in and out of the sockets with ease.

Next, turn on the car head unit and listen in such a way that you can see if the sound comes from the speaker after switching all the fuses. If it is not, you will need to solve some other electrical issues, like a rarely used component or blown-up rear fog lamp fuse.

Enabled Protected Mode

Most audio equipment features an anti-theft mechanism. During a power outage, this mechanism is affected. A dead battery or loose wiring can cause the protect mode to turn on.

An anti-theft secured automobile audio unit must heat a different warning and either not work or ask for a code. You may need troubleshooting processes or enter a code to repair the issue.

Take the manufacturer’s instructions and check for more information. If your car stereo does not have an anti-theft feature and the screen is black, the problem is due to another reason.

Improper Head Unit Wiring

When inspecting the wiring, you have to access the head unit’s backside initially. You cannot remove the car stereo easily because it is designed to be an anti-theft strategy. If you need to remove it, ensure not to harm the head unit or dashboard.

You will need to drag the head unit slowly from the dashboard. Check every connector and cable to know if they have gotten loose. Cover your probes with protective rubber caps to avoid short-circuiting the vehicle.

You also have to look inside the dashboard to see if there are loose connectors. Then, turn on the car stereo if it works well before replacing the heads unit.

Anti-theft Security Measures

Some car radios come with a feature prohibiting them from working during a power outage. This anti-theft measure renders the car audio useless.

A dead or disconnected battery is the most common reason for the car stereo not to turn on but with power. It is indicated by a different or limited display on the radio. It is recommended to consult the car manual to troubleshoot this issue.

Faulty Power At The Head Unit

Most car radios come with two power wires. The first power wire always stays hot and powers the memory, while the second one only gets hot once you switch on the ignition key. Your car stereo will not work correctly if the two power lines are inverted.

You will likely deal with a damaged wire if you have no head unit voltage but with automotive fuse block power. This requires you to determine the source to repair. You can test the twelve-volt switch wire or the ground wire to see if they are faulty.

Faulty Pigtail Connector

Did you just install a new head unit, but it won’t come on? Then, the wiring could be the issue.

This is where you need to remove the car stereo to determine the cause of the issue. The head unit pigtail connector must be properly attached. To ensure the electrical connection, you can take the connector in and out back.

Next, use a test light or voltage meter to check the red accessory 12V wire, yellow constant 12V power line, and black ground wire. You have to check if the cables are properly activated. Beware that the wire must contain 12V all the time, even if your vehicle is turned off.

Once you turn on your automobile, the red wire must only contain 12V. You can try this wire on another metal ground to determine whether or not the ground battery works.

The wiring of an aftermarket stereo is different from the OEM systems. You will find six wires, in particular audio devices. During the diagnostic process, remove the head unit as it will help you quickly access the factory wiring. Check if the pigtail connector is positioned correctly in the head unit.

Damaged Power Button

Verify if the power button is actually working. To do this, you need to press and hold the power button for a few seconds. If the head unit does not turn on, then you need to replace this button.

To fix this issue, you must disassemble the head unit carefully by removing all the screws. Next, locate and remove the power button. You can purchase a new button and install it in the same way you removed the old one.

How to Fix A Car Stereo That Won’t Turn On But Has Power

First, you need to remove your car radio from its DIN position. A car stereo removal tool set will help you fit into the notches on every panel side. You will also use it to extract the head from its mounting bracket.

You must see wire groupings linked to wiring harnesses on the head’s back. The wiring harness can divide accessories, power, and speakers into 2 or 3 regions. Ensure there are no loose wires that enter the factory harness.

You have to make sure that the harnesses are connected properly to the automobile stereo. You also need to find the constant wires and ground terminal.

After preparing the multimeter, you need to set the DC setting on it. The negative probe should be on the good ground terminal, while the positive probe must be positioned on the constant wire.

Meanwhile, you will need to check the fuses if the multimeter does not show value. If there is constant wire voltage while the device shows values of approximately 12 Volts, you can then test the twelve-volt switch wire. Remember that the yellow wire should always have 12 voltages.

You can check the owner’s manual for constant wire issues. Avoid connecting cables to the negative battery post. There should always be a ground presence in the car. Ground wires are usually green. Check if there is any voltage on the constant wire with the multimeter’s testing leads.

Signs To Look For When Car Radios Won’t Turn On

Here are the signs that your car stereo will not turn on but has power:

The car stereo’s sound and display turn on and off simultaneously, indicating that the head unit does not receive enough power.
There is a ground or power issue if the car stereo cuts off a few seconds unpredictably.
When the car stereo shuts off and travels over a bump or negotiates a corner, there is a big chance that it is due to the loose connector in the back of the audio device.
The car stereo does not turn on whether it is a blown fuse or a wiring issue.

What To Do If the Head Unit Loses Power?

You can bench test the head unit outside the vehicle to see if it is still working. Make sure to use the same ground when testing the head unit. If the problem persists, you may have ground loops caused by improper insulation of the head unit.

Most car head units typically have one or two fuses that will burn out if there is a power surge. Try to replace the fuses with the same amperage and see if that solves the problem. If you don’t replace a blown fuse, the car radio will fail to work properly.

Here are some of the tried and tested tools you can use to fix car audio issues:

Screwdrivers
Multimeter
Socket set
OBD diagnostic scanner

These tools can come in handy when you are trying to fix car stereos or audio units.

Last Tips To Use If Your Car Stereo Won’t Turn On

Fixing a head unit that won’t turn on can be a challenge. But with the right tools and a bit of patience, you can get your car radio working again in no time.

If you suspect that the problem lies in the head unit, the first thing you should do is to check the ground wire. Here are a few more things you can do if your car stereo won’t turn on:

Make sure that there is a ground presence.
Check the car fuse box under the hood or in the vehicle.
You may need to repair or replace your car stereo if it doesn’t turn on, but it has power.
Test the twelve-volt switch wire.
Verify that the unit is not in anti-theft mode.
Check the fuses’ power with a multimeter or a test light.
Replace the power wires if they are in bad condition.
Make sure the audio unit has a proper power supply.

Fortunately, with a little debugging and damaged wire replacement, your car radio will be up and running again. If not, it is advisable to take it to the authorized service center for a professional repair.

The best thing you can do is to go to a repair shop so that they can bench test the head unit. With that, they can properly diagnose the problem and know what to do next.

Last Updated on: October 23, 2024

Hi, my name is John Snow and I am a car lover. With two decades under my belt fixing and driving cars, I'm always on the hunt for fresh, cutting-edge methods to give my ride a performance boost. Driven by my zeal to decode car problems, I'm on a mission to equip vehicle owners with accurate and handy tips. By doing so, they can fix their rides while saving both time and cash.

By John Snow