Why Car Radio Won’t Turn Off? Fix it Like a Pro.


If you have a radio or stereo system in your car and it’s suddenly you cannot turn it off, you may be worried about it draining the battery or messing with other systems in your car.

So, what causes the car radio to not turning off, and how to fix it? Let’s find out.

In general, the car radio won’t turn off because of incorrect wiring of the switch or faulty memory wire. There are also other reasons that include a faulty ignition switch, or a damaged door switch.

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Tip: Although running a car radio without a running engine may not seem to be a big problem, but when it does for a long time, there is a high risk that your batter will be drained and you will be unable to start your vehicle.

It is really important to have radio connected through an ignition system which may be difficult without the original harness. To makes sure your radio has the correct wiring, check out these replacements of original stereo harnesses on Amazon.

In this article, I will cover the wiring aspects of radio and how it relates to situations of your radio not turning off. Then I will look at other factors on when and how your radio should and does turn on and off. 

These factors will regard car ignition systems and radio wiring concepts, and finally, I will explain how to turn your radio off and if the radio has any impact on your car battery. 

How does a car radio work?

Wiring for a car stereo (radio)

If your car radio won’t turn off or it is intermittent (turns on and off frequently), the first thing you will have to do is to pull it out and check the wiring.

This could be overwhelming when you remove the head unit to find the harness with many colored wires. Which one is which, and how would you test to see if they are working correctly? 

why car radio wont turn off

Yellow car radio wire

The yellow wire is termed the constant. This means that it has a direct line to the car battery and provides power (12 volts) to the radio, and features like a memory backup. We will go into more detail about the constant wire and its effects on your car radio’s functioning.

Blue car radio wire

The blue wire is a remote turn-on or power antenna wire. This wire actually provides 12v out, and the signal comes directly from your radio. This wire will trigger a power antenna, an antenna amplifier, or the factory amplifier.

Green car radio wire

Then you have a set of green wires. One being completely green, and one is green with a black line through it. These wires are your left rear speaker leads. Green Being the positive lead, and green/black is negative.

Purple car radio wire

As with the green set of wires for your left rear speakers, we have a set of purple cables, which are precisely the same except they function to support the right rear speakers. The purple lead is positive, and the purple/black is negative.

Black car radio wire

The black wire is your car radio’s ground wire. We will discuss this further in the following sections and how it could affect your car radio.

Red car radio wire

This is termed the accessory wire, and it turns on with the key. This wire triggers the radio to turn on. We will also cover this wire in more depth.

White car radio wire

The set of white speaker wires function the same as the set of purple and green wires; however, these are for the left front speaker channels, White being the positive and white/black being negative.  

Grey car radio wire

The last set of speaker wires you will get is the set of grey wires that will function for the right front speaker channels. Grey being the positive and grey/black being negative. 

Orange car radio wire

The last wire you get is orange, and this is typically the illumination wire. In some vehicles, it is called a dimmer wire. Occasionally you will see an orange and black wire labeled dimmer. Typically, these have the same function, except the dimmer (orange/black) wire will adjust up and down between 0v and 12v as you make adjustments to your interior dashboard lights.

Hence the illumination wire being 12v, it is either on or off, while the dimmer functions as a rheostat (a device used to control a current by varying resistance).

When should the car radio turn off?

Depending on your car model, car stereo set up, and how it has been wired, the radio can turn off in a few ways. However, a standard OEM car radio will be designed to turn off, specifically when specific criteria are involved. Let’s go over them.

The car radio should turn off when turned off manually.

The radio will turn off when you manually turn it off. That means you physically have to press the power button or use the remote (if the radio comes included with one). 

The car radio should turn off in the ignition start position.

The radio in your car should turn off when the vehicle is started, not when the keys are in the first stage of the ignition, and there is no bypass of the car’s electronics.  

Many cars built many years ago were not as powerful, and old batteries had issues handling the load of the starter motor. When car designers realized this, they implemented a bypass in the ignition cycle. 

When the key is turned, the ignition circuit is closed, and that sends power to the starter motor bypassing all the circuitry in your vehicle (radio, wiper. Fans, etc.).

You will notice this when the radio is still powered with the ignition set to “on” but shuts off in the “start” position. 

The car radio should turn off when the car is switched off.

When you turn off your car and remove the keys from the ignition, this breaks your car’s closed electronics circuit. Hence, all electronics in your vehicle will shut off (radio, wiper, fans, etc.). 

However, with today’s modern cars, some automotive manufacturers ‘ circuits are built differently. Some radios will receiver power for about ten minutes or until a door is opened and only then power off.

Keep this in mind if you are driving a new car and you are wondering why it does not turn off when you stop the car and remove the keys. 

Why does the car radio stay on with the ignition off?

The reasons are pretty straightforward and relate to why the radio switches off when the car is started. Additionally, some car fanatics and car audio enthusiasts may choose to wire their radio differently from the standard setup.

The electronic circuit structure of a car radio

As we said previously, a car is wired to bypass the electronics circuit when the ignition is in the “on” position. When the keys are in the car, and they are in the “off” position, the turned key still closes the electronics circuit, enabling the car radio to turn on. 

This setup is standard in all cars because of the previously implemented design when manufacturers discovered that it is difficult to start the engine with so much add load to the starter motor while the car’s electronics were also on. 

Switched live (red wire) and memory (yellow wire) wiring concepts.

As we discussed, the yellow wire for your car radio is the constant, always drawing power and acting as a memory wire. This is so your radio can always have the correct date, time, radio presets, EQ presets, and saved presets even when you turn your car off or left off for extended periods. 

You then have the red wire that acts as a trigger to turn the car radio on when the keys are in the ignition. 

Some car audio enthusiasts prefer to have the switched wire (red) and memory wire (yellow) permanently live. This allows the radio to be on and continually play even when the keys are out of the ignition. 

You would have to physically turn off the radio then, via a power button or remote if the radio had one. Keep in mind that if you do not turn the radio off, then it would drain the battery.

What could other reasons be causing my car radio not to turn off?

We discussed a few reasons why your car radio won’t turn off and the reason it will turn off in certain situations; however, there could be situations where your car radio just does not turn off.

For instance, it would stay on when you try to start the car, or perhaps when the doors are opened, and even when you try to switch it off manually. The main reason for this would be wiring complications, which we will go over.

Incorrect wiring will keep your radio from turning off.

If you have installed an aftermarket stereo and have wired it yourself, the problem could lay with how you connected your radio’s wires. Although not difficult and complicated, you need to pay attention to what wires are for your radio’s functions. 

You may have mistakenly connected the wires to the incorrect connection points, causing your radio to stay on. Check that your yellow wire (memory wire) and red wire (your trigger wire) is connected to the valid connection points.

If not, you may have the setup that we discussed earlier. 

A faulty ignition switch will keep your radio from turning off.

This does occur, and a faulty ignition switch may keep your radio from turning off. We no know that your car radio should turn off when the ignition starts and should only stay on when the ignition is in the “off” position. 

To troubleshoot this problem, see if your radio stary on when you start the car, and if it does, the problem is most likely a faulty ignition. 

In older model cars, ignition is easy to replace and relatively inexpensive; however, if you have a modern vehicle that works with software, electronic systems, and circuitry, you will need to have it repaired by a professional. 

Shut-off delay problems will keep your radio from turning off.

Although less common than the other two examples, some radios can be faulty, and when they are programmed to shut off after 10 minutes or when a door is opened, the radio could still stay on.

You can refer to the owner’s manual to see if the radio in your car has this function. Just keep in mind that radios that are over 15 years old may not have this function.

If your radio does not have this feature, the problem could perhaps lay with a faulty door switch. To troubleshoot this, all you need to do is open and close the doors. Then check if the light on the roof of your car is turning on and off. If it is not while the door is open, then the problem may be a faulty door switch. 

If you think that the shut-off delay is acceptable and your door switch is working correctly, the last two options are your best bet to troubleshoot the issue; otherwise, you would need to consult a professional.  

In most instances, you can take the car to the dealer, and they can set the radio correctly, while in other cases, the radio might be faulty, and you would need to replace it. 

How do I turn off the car radio in my car?

We now know precisely how a car radio functions and when it should turn off and on and hence there are three ways to turn off your car radio, and if these three ways do not work, then you will have to troubleshoot the cause of the problem as we have helped you to do. 

  • Manually turn off the radio using the power button or remote.
  • If the keys are in the ignition, then set the ignition to the “off” position.
  • If the car is off and the keys are out of the ignition, then open a door.

These are the three ways you can use to turn off your car radio. One thing to keep in mind is that there may be other power switches located on your car, such as on the steering wheel. You would then be able to turn it off from there if it allows you to; however, these are the three most common ways.  

Should I turn off my car radio before I turn off my car?

With older cars, if the radio is still on prior to turning off the engine, it would cause a bit of a battery drain, decreasing the car battery’s life. 

In modern cars, this is not the case because of the circuits’ design allowing the car radio to turn off automatically and not drawing enough power from the battery to do any harm. 

Can leaving the car radio on will kill the battery?

If you have a standard OEM factory radio, then the chances of your battery being drained while the radio on is slim to none. It is more likely that using the heater and air conditioner while the car is off will drain your battery. 

Nevertheless, you should consider aftermarket systems with large amplifiers and subwoofers that tend to draw a lot of power. In addition to that, infotainment units with touchscreens with lights and many buttons and knobs will also draw more power from the battery than a standard factory OEM unit. 

These systems would have more chance of draining your battery at a faster rate. Still, you would be able to play the radio for a couple of hours without the heater before your car will lose any significant amount of battery power. 

Conclusion

By understanding the wiring of a car radio, how the ignition system works, and that some radios have shut-off delays, you can troubleshoot why your car radio will not turn off.

These concepts are not difficult to understand; you should just take note of each aspect and correlate them to the problems you are having with your radio, and you will be able to solve and fix the issue.

More than likely, it will be something that is minor and can be fixed without going to the extremes of purchasing a new radio or getting your entire car rewired. 

Your car radio’s main aspects to why it is not turning off was a wiring issue, a car ignition issue, or shut-off delay issue either from the radio itself or the door.

Martin

Welcome to ImproveCarAudio! I am Martin, and I love to write about everything related to car sound systems. I strive to provide the most accurate and helpful information about car audio through extensive research, as well as my experience with car audio installations.

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