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Why Car Radio Won’t Turn Off?

Nobody wants a car radio that won’t turn off when you take the keys out of the ignition. This is not only pretty annoying, but it can have negative consequences for your battery.

If left unchecked overnight, a car radio can leave your battery completely drained. This can happen even faster if your battery is near the end of its life.

So, what are the reasons why car radio won’t turn off? I’m going to take a look at the most common reasons why this happens and arm you with the information needed to fix this irritating problem.

The Reasons Why a Car Radio Won’t Shut Down

The Reasons Why

When this happens, it’s usually the result of one of a few common problems. Thankfully, they are relatively easy to diagnose and solve. 

By far… 

The most common reason a car radio won’t turn off is incorrect wiring of an aftermarket radio installation. Most likely, a mistake was made when connecting the head unit wiring.

Failing that, the ignition switch or some other component related to the radio shutting down is probably faulty. Some car models don’t automatically kill the radio when the key is removed from the ignition. They have a timer that will allow ten minutes or so of radio power. Or will only shut down when you open a door.

Head Unit Wiring

If you have recently had a new head unit installed and now the car radio doesn’t switch off, it’s almost 100% certain that whoever installed it wired it incorrectly. In this scenario, you should return it to the shop that did the installation and get them to correct the mistake.

It’s probably best to let a professional handle the rewiring. Especially if you did the original installation and now can’t get the car radio to automatically turn off. But, if you think this is a job you can do yourself, then you’ll need to know a little about the various wires involved.

All head units have several different colored wires that need to be connected properly. The green, purple, white, and grey wires are all related to your front and back speaker connection. The orange wire is related to your dimmer settings. There’s also a black wire which is the radio’s ground wire.

The basics…

We can generally ignore all of these wires when it comes to the issue of why car radio won’t turn off. We need to direct our attention toward the red and yellow colored wires which control the power.

The yellow wire is what is referred to as the constant. This means it is directly connected to your car battery at all times and never goes off. That’s so any saved presets, such as your favorite stations and the time, will be remembered each time you turn the car on. 

The red wire is referred to as the accessory wire. This is the wire that provides the main source of power for your radio. It only becomes live when you turn the key in the ignition and turns off when you switch off the engine.

The usual suspect…

If these two wires are connected the wrong way round (the yellow wire is the one providing the main power source), your car radio will remain on all the time as the power supply is constant. 

A simple switch of these wires should fix a car radio not turning off. You can also use a voltmeter to make sure that both wires are functioning as they should. 

Ignition Switch Issues

Ignition Switch Issues

If you have used a voltmeter and you discover that the red wire is also running hot when the key is removed, there could be a problem with your ignition switch. 

Likewise, if both yellow and red wires are running hot when the key is out of the ignition, this means there will be a constant supply of power to your radio. And, various other accessories in your car also. 

In this situation, you’ll probably be able to turn on your wipers and open windows without the keys in too. If that’s the case, a simple realignment of the cylinder or a replacement of the ignition switch should solve the problem. 

What to do?

Diagnosing this as the problem will differ depending on the model, make, and age of your car. Wiring diagrams may need to be consulted. You’ll need to identify the accessory relay circuit and check that it isn’t being activated when the ignition is off. If this is beyond your skill level, seek professional help.

Worn Out Key or Ignition Cylinder

Older cars may be suffering from a worn key or ignition cylinder. When you turn the key in the ignition, the position before you start the engine is called the accessory position. This enables you to turn the radio on and use other car accessories without starting the engine.

If you can remove the key from the ignition when it’s in the accessory position, then the cylinder and key are probably worn out from overuse. You can address this by simply making sure the key has been turned to the off position before it’s removed. 

If you want to remove any chance of error, then you will have to replace the cylinder completely.

Is Your Car Radio Designed to Stay On?

Designed to Stay On

As mentioned, some manufacturers design the electronics of the radio to stay on for a set time after you shut the car down. Usually, this will be for around ten minutes. Or when a car door is shut.

If you have the original manufacturer’s radio unit installed and it doesn’t turn off when you exit the car, or after a designated time, then it’s probably an issue with the trigger mechanism. Or the switch in your door.

How to test this… 

First, remove the keys from the ignition. Next, get out of the vehicle and close the door behind you. Use a stopwatch to see how long it takes before the radio turns off. If it closes down by itself, then that’s a feature of your car and nothing to worry about.

If the radio fails to turn off and you’ve checked everything else, then you may have a problem with your door switch. You can check on this by seeing if your dome lights go out when the door is closed. 

Normally, these kinds of problems are hard to fix with a simple DIY solution. So, you’ll most likely have to take your car to a professional to get the job done.

Need Some Help with Your Car’s Audio System?

We can help with that. Take a look at our handy articles on How to Reset Kenwood Car StereoHow to Remove Car Stereo Without KeysHow Much Does It Cost To Install A Car Stereo, and How Do I Get Sirius Radio In My Car for more useful information.

Want a better sound in your ride? If so, check out our in-depth reviews of the Best 3000 Watt Amps, the Best 2000 Watt RMS Amps, the Best Monoblock Car Amplifiers, and the Top Best Car Amplifiers you can buy in 2023.

And, don’t miss our comprehensive reviews of the Best Car Subwoofers, the Best Under Seat Subwoofers, the Best 6×8 Speakers, and the Best 6.5 Speakers currently on the market.

Why Car Radio Won’t Turn Off – Final Thoughts

Now you know the main causes of why a car radio won’t turn off. Hopefully, you can make the correct diagnosis of why this is happening in your vehicle.

If the problem is wire related, and you understand the basics of car radio wiring, then you can probably solve the issue without professional help. 

However, if the culprit is an ignition switch or cylinder issue, you should only fix it yourself if you are sure you know what you’re doing. Most shut-off delay problems will necessitate calling the pros in. Whatever the problem is, we hope this article has been of use in helping you identify it.

Until next time, good luck and happy listening.

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About Joseph L. Hollen

Joseph is a session musician, writer, and filmmaker from south Florida. He has recorded a number of albums and made numerous short films, as well as contributing music to shorts and commercials. 

He doesn't get as much time to practice and play as he used to, but still manages (just about!) to fulfill all his session requests. According to Joseph, it just gets harder as you get older; you rely on what you learned decades ago and can play without thinking. Thankfully that's what most producers still want from him.

He is a devout gear heat and has been collecting musical instruments all his life. As his wife, Jill, keeps on saying, "You're very good at buying nice instruments, but terrible at selling them!".

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