Car Radio Only Works In Accessory Mode – Fix 100% In 2024

Many drivers, including myself, have encountered the problem of a car radio only functioning in accessory mode. It’s frustrating when the stereo fails to work properly while the engine is running, especially during long drives when entertainment and information are essential for a pleasant journey.

Car Accessory Mode in car is due to various factors, such as a dead battery, a faulty ignition switch, blown fuses, loose connections, or a faulty radio, which require troubleshooting and potentially costly repairs or replacements.

This article will discuss the possible causes of why your car stereo only works sometimes and what steps to take to resolve it.

Car Radio Only Works When Engine Is Off

When a car radio functions only when the engine is off, it suggests an electrical issue related to the power supply or interference from the engine’s electrical components. This could be due to a faulty connection, a damaged wiring harness, or an issue with the alternator. When the engine is running, it might be generating electromagnetic interference that disrupts the radio’s signal.

Causes Of Radio/Stereo Only Works With Key In ACC Position:

What is Accessory Mode in Car? Suppose a car radio/stereo only works with the key in the ACC (Accessory) position. If so, the stereo won’t get power when the engine is running or the key is ON, only when switched to the ACC position.

Let me help you diagnose the issue of your car radio only working when the key is in the accessory (ACC) position.

1. Dead Battery:

A dead battery is the most common reason the radio has sound in accessory mode but not with the engine. If the battery is dead, the car’s electrical parts will not work correctly, including the stereo.

 Dead Battery

2. Faulty Ignition Switch:

Another possible cause of the radio only working in accessory mode is a faulty ignition switch. The ignition switch powers the car’s electrical parts, including the radio. If the switch is broken, it cannot adequately supply the radio with adequate power.

Faulty Ignition Switch

Also Read: What Does Traf Mean On A Car Radio

3. Blown Fuse:

A blown fuse can also cause the radio to only work in accessory mode. Fuses protect the electrical parts of the car from power streams and overloads. If a fuse blows, the electrical part it covers will not work correctly.

4. Loose Connection:

Car starts but radio doesn’t work? A loose connection between the radio and the car’s electrical system can also cause the radio to only work in accessory mode. It can happen if the wiring harness is not connected correctly or the connectors are loose.

Loose Connection

5. Faulty Radio:

Finally, a faulty radio can also cause the issue of only working in accessory mode. If none of the above causes constitutes the problem, it’s possible that the radio is broken and has to be fixed or replaced.

Faulty Radio

6. Outdated Software:

Radios installed in more recent vehicles need software to function. Such software may start to malfunction for a variety of causes.

One outcome is that the radio might only function in accessory mode. Although it is not a frequent cause of this issue, it is worth investigating.

How To Fix A Car Radio That Only Works With Ignition On?

Now that we know the possible causes of the car stereo turning on and off repeatedly. Now let’s look at the steps to resolve the radio randomly working; it always works in accessory mode.

To rectify the problem of your car radio functioning solely when the ignition is on, here are some tried-and-tested fixes:

1. Check The Battery:

Why does my radio only work sometimes? Checking the battery to determine if it is dead is the first step. Try jump-starting the car or changing the battery if the battery is dead. When the battery is functioning correctly, the radio should also be faultless.

Check The Battery

2. Check The Ignition Switch:

The ignition switch should be examined if the battery is not the problem. To determine whether the switch is giving the radio adequate power, test it with a multimeter. The switch must be changed if it is broken.

Check The Ignition Switch

3. Check The Fuses:

If the ignition switch is not the issue, then check the fuses. Locate the fuse box in the car and replace any blown fuses. Checking all the fuses to ensure they function properly is another smart move.

 Check The Fuses

Also Read: What Is SCV In A Car Radio

4. Check For Loose Connections:

If the fuses are not the issue, check for loose connections between the radio and the car’s electrical system. Check the wiring harness and connectors and ensure they are securely connected.

 Check For Loose Connections

5. Replace The Radio:

Finally, if none of the above steps resolves the issue, the radio may be faulty and need replacement or repair. A professional mechanic can diagnose the problem and recommend the best action.

6. Update The Software:

Please ensure you update your radio’s software if it needs to run effectively and function as intended. Some automakers offer updates designed particularly to enhance performance or address potential problems with current software versions. Following the manufacturer’s instructions, you must update the radio software to the most recent stable version.

Car Stereo Won’t Turn On With Ignition:

If the car audio doesn’t activate with the ignition, check for grounding issues. Look for wire corrosion and inspect the pigtail’s connection to the ground. Wires might be detached or need to be reconnected to a better ground.

Radio Doesn’t Work When Car Is Running:

A common reason for a car radio not working is often a blown fuse. This occurs when the electrical circuit becomes overloaded, leading the protective fuse to blow and interrupt the power supply to the radio. Wiring problems could also contribute to this issue.

Why Does My Car radio Not Work Sometimes?

Intermittent operation of a car stereo often indicates wiring issues. However, depending on the specific symptoms, other factors could contribute, such as problems with the amplifier, internal faults in the head unit, or issues with speakers or speaker wires.

Why Wont My Car radio Turn On But Has Power?

Car Stereo Won’t Turn On But It Has Power? A prevalent issue with faulty car stereos is poor wiring conditions. This can include damaged, aged, or improperly connected wires. Additionally, certain car stereo models incorporate built-in fuses to safeguard against sudden circuit problems.

Car Radio Not Powering On:

The primary culprit for your radio suddenly ceasing to function is often a blown fuse. Every car radio is equipped with at least one fuse, serving as protection against power surges originating from other parts of the vehicle. When your radio stops working, the first step is to inspect its fuses and replace any that are blown.

1. Does The Ignition Switch control The Radio?

Yes, the ignition switch governs the radio in a car, supplying power to the vehicle’s electrical components. Turning the key to ON or ACC activates the radio, while switching it OFF cuts power to the radio.

2. How Do You Know If Your Ignition Fuse Is Blown?

To know if your ignition fuse is blown, check if the ignition switch doesn’t start the engine, check if other electrical parts are working, and inspect the fuse for signs of damage or a break in the wire inside it.

3. What Happens When You Turn The Ignition Switch To An Accessory?

In the accessory (ACC) position of the ignition switch, the automobile’s electrical system, including the radio, is powered without starting the engine. This allows you to use accessories like the radio without draining the battery or engaging the starter.

4. How Long Can I Leave My Car In Accessory Mode?

Leaving your vehicle in accessory mode for extended periods is generally acceptable, but it’s advisable to limit it to a maximum of two hours, especially if you’re heavily utilizing accessories. This helps prevent draining the battery excessively.

5. Why Does My Radio Have Power But Won’t Turn On?

Faulty stereo power wires: One remains permanently off, while the other activates only with the ignition. If roles are reversed, the stereo won’t function. Replace if no voltage.

6. How To Put Car In Accessory Mode?

Nowadays, nearly every new vehicle I drive has a push-to-start ignition system. To start the engine, press the start button while stepping on the brake pedal. Don’t depress the start button; press the brake pedal to enter auxiliary mode. All there is to it is that.

7. How Do I Reset My Car Radio?

Use the tool to press and hold the reset button for a few seconds. This action will reset the radio’s settings to their default or factory state. Some car radios have a reset button that can be pressed using a small tool like a paperclip.

8. How Do I Turn Off Accessory Mode?

  • Press ENGINE START/STOP once without pressing the brake pedal for Accessory mode.
  • Press it again for On mode.
  • To start the engine, press and hold the brake pedal, then press ENGINE START/STOP. Keep your foot firmly on the brake pedal during engine start.

9. Why Wont My Car Go Out Of Accessory Mode?

If your car remains in accessory mode, try starting the vehicle and then turning it off. Ensure the vehicle is in park to exit accessory mode.

10. Why Is My Car Key Stuck In Accessory Mode?

If the key is stuck in accessory mode, it may indicate a problem with the ignition switch or the key itself. Ensure the car is in park and try wiggling the shifter while turning the key to release it.


A car radio that only works in accessory mode can frustrate drivers and passengers alike. However, several things might cause the problem, such as a dead battery, a broken ignition switch, blown fuses, weak connections, or a malfunctioning radio.

By following the steps outlined in this article, drivers can diagnose and resolve the issue, ensuring that their car radio functions correctly and provides the entertainment and information they need on the road.

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