Aftermarket Radio Causing Electrical Problems [5 Easy Fixes]

It’s common to find aftermarket radio causing electrical problems like not having power, keep blowing the fuse, draining the battery, getting poor reception, and making a whining noise from the alternator.

Keep reading this article to know more about these common aftermarket radio problems and find out how you can fix each of these issues. You’ll also learn how to connect aftermarket radio wires in this guide. Let’s begin!

radio causing electrical problem

Aftermarket Radio Causing Electrical Problems [5 Easy Fixes]

Aftermarket radios can create a wide range of electrical problems if they’re not installed correctly. Here are the most common problems that you can face after installing an aftermarket radio in your car and how you can fix them:

Note: You can also read how to fix the Starter Fuse keeps blowing problem.

1. Aftermarket Radio No Power

Why is your aftermarket radio not getting power? When the aftermarket radios draw too much electrical current, it can blow the fuse. It’s not uncommon for aftermarket radios to do that and it won’t get any power once the fuse is blown.

Checking for a blown fuse is simple. You have to locate the fuse in the fuse box of your engine bay or dashboard and see if it’s damaged. You can see through the fuses and if the link between them is broken, that means the fuse is blown.


Another potential reason for the aftermarket radio not turning on is when the wires are switched up during the installation process. The wires are also sometimes connected loosely and they don’t make a good connection.


Replace the blown fuse and that should solve the problem, at least temporarily. If replacing the fuse solves the problem, then you’re good to go. But if it keeps blowing, that means you have to diagnose this issue further.

Many people increase the amperage of the fuse to solve this problem and keep it from blowing again. But doing that doesn’t mean that the issue is fixed and you can end up burning an important component by doing it. Use the fuse of the correct amperage only and keep on diagnosing the issue.

If it doesn’t turn on after you replace the fuse and you’re still wondering why is my aftermarket radio not turning on, uninstall the radio and check for loose connections. Make sure all the wires are connected in appropriate slots and the connection is secure. 

2. Aftermarket Radio Keeps Blowing Fuse

If you replace the fuse once or twice and see that the aftermarket radio continues to blow the fuse, the most common reason behind it is wiring issues in your radio.

These wiring issues are normally caused when you don’t disconnect the battery at the time of installing the radio. That can send a voltage spike anywhere and make it difficult to trace where the electrical fault is.

The first thing you should check is the wiring harness and see if that’s alright. Then, check the wiring of your radio to the components it’s connected to one by one and see if you can find any loose connections or other wiring issues.


If there are any wiring issues with your radio, you have to replace them. You have to replace the wiring harness and install the radio again while disconnecting it from the battery to fix the issue.

3. Aftermarket Radio Causing Battery Drain

If you’re wondering can an aftermarket radio drain battery, the answer is it can absolutely do it. A common indicator of this problem is you’ll be able to turn on the radio even after turning the key off.

This issue is also caused by an installation mistake. Connecting the power wire of the aftermarket radio directly to the stock radio’s power line causes this problem. Aftermarket radios cannot be connected to stock radio’s power in most vehicles.

auxiliary power resource

Stock radios are able to communicate with the ECM of the car and they know to turn off automatically when the ECM shuts down. But aftermarket radios don’t have that mechanism built-in and that’s why they stay on and drain the battery even when it should be turned off.


These aftermarket radios need to be connected to an auxiliary power source to function properly. Doing that ensures that the radio will only have power when the key in the car is turned on.

Run the power wire from an auxiliary source instead of the main radio and that’ll keep your car’s battery from being drained.

4. Aftermarket Radio Poor Reception

Getting only one or two stations when you’re driving can be a real pain. When an aftermarket radio has bad reception, it’s because the antenna hasn’t been properly installed. You’ll find that the aftermarket radio sound cuts out in the limited stations that you get when you have poor reception.


The blue cable that comes with most aftermarket radios usually powers the antenna. And during installation, many people don’t connect it to anything and just leave it on as it is. That’s what causes this issue.


Connect the blue cable to the 12-volt power source ignition and that’ll solve your problem. The power source ignition wire is normally red. Don’t plug into the yellow wire is normally a constant.

Once you’ve taped the blue cable into the red wire, your aftermarket radio’s antenna should be fully powered and show you a lot more stations according to your location. The problem of the sound being cut will also be solved.

5. Aftermarket Radio Causing Alternator Whining Noise

Alternator wine occurs when there is bad ground to the head unit or the amplifiers of the radio. One of the most common symptoms of a bad ground car audio is you’ll hear a whining noise coming from your vehicle when the RPMs fluctuate and it’ll gradually lessen when the engine is turned off.

It happens because the radio is drawing too much power from the alternator and the alternator isn’t able to keep up. The headlights in your car can also become dimmer when you turn up the radio because of this issue.


The first solution you should try to fix this problem is to install a capacitor. It can create a constant flow of 12V current and it can fix the spikes in the power draw from the battery to the alternator.

If adding the capacitor doesn’t make the radio run normally, your next option is to replace the alternator in your car with a better one. Your current alternator isn’t generating enough power to keep the radio running smoothly and replacing it with a more powerful one might do the trick.

You can also replace your current battery with a bigger battery or add an auxiliary battery if you want to give your maximum effort into solving this problem. Doing it will generate more power and prevent the alternator from that annoying noise.

How To Wire A New Stereo In An Old Car

It can be a little difficult to install an aftermarket radio in a classic car as ready-made parts for such cars cannot be found easily. Before you get started with installing a new radio, make sure that you disconnect the battery first.

You can install a new radio in your old car if you have a good idea about the wiring. Here are the wiring specs in detail:

Yellow Wire

The yellow wire is the constant. You must run it to the 12V dashboard signal or your battery and make sure that it’s fused.

Black Wire

The black wire is for the ground. You can ground it through the chassis or the harness as long as there’s good ground with no resistance.

Red Wire

The red wire is the ignition power wire that acts as a switch signal and it turns on the radio when you turn the key on. Connect it to a 12V switch source that’s hot only when the key is on. If you’re wondering why my aftermarket radio stay on all the time, maybe you didn’t connect this wire properly.

Blue Wire

The blue or white wire is for the amplifier. You need to connect it to the amplifier once you locate it. Leave it if you don’t have an amplifier.

Other Wires

The rest of the wires are speaker wires. These wires will be different for each car as the specs of the radio is slightly different in each car.

There’s no wiring harness available for these wires and you’ll have to connect them manually. That’s why so many people make mistakes when they install an aftermarket radio.

Most of the problems that occur in an aftermarket radio come from mistakes in the installation process. So, be patient and careful when installing an aftermarket radio to avoid these problems for good.


Why does my radio have power but no sound?

When the radio turns on but doesn’t have sound, that means it’s getting power but one of the components is damaged which leads to no sound. The common reasons behind it are a wiring short or damaged speakers.

Why does my aftermarket radio have static?

Radio static is generally caused when the antenna makes a noise. Check if the noise is coming from the other sources and if it only comes from the radio, that means the antenna is causing the problem.

Why did my aftermarket radio stop working?

If your aftermarket radio has stopped working all of a sudden, it usually happens due to a blown fuse. If that’s not it, it can also happen due to a bad antenna, damaged speakers, or anti-theft measures.

How to stop electrical interference on the radio?

The main things you can do to stop electrical inference on the radio are to make sure that the cables aren’t too long and the connections are good.


Many people prefer aftermarket radios as it gives them an opportunity to save money. But to find the aftermarket radio causing electrical problems is frustrating and may often seem like a lost cause.

But with the help of this guide, now you know what are the typical reasons that make the aftermarket radios cause problems and how you can address each of these issues. Leave a comment below if you have any more questions about aftermarket radio issues.

About John M

John contributed as a technical head at an automobile company just 2 years after his post-graduation in Automobile Engineering. He loves to lead a free life, so he left his job & started blogging. Now, he does research on every automotive problem, part & product and seeks a better solution & best products & shares his findings with his readers to help them as well as to minimize their struggle.

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