Illumination Wire on Car Stereo: Where & How to Wire

Car stereos are interesting, with many parts working together to create great sound. One important component is the illumination wire.

Although it doesn’t directly affect the sound quality, it plays a crucial role in providing a good stereo experience, particularly when driving at night.

In this article, we will provide you with detailed information to help you understand what it is and how to connect it to your car’s stereo.

What is the Illumination Wire, and How it Works

The illumination wire, also known as the dimmer wire, is like the “light switch” for your car stereo. It’s the wire that controls your car’s main light system. So, when you turn on your headlights, the brightness of the dashboard, including the stereo’s display, dims.

The stereo screen dims too, thanks to the illumination wire. Moreover, this wire makes sure your stereo’s light isn’t too bright when driving at night, keeping everything just right for your eyes.

Illumination Wire on Car Stere: Where to Connect

With the illumination wire, you’ll generally find it at the back of your car stereo system. It’s typically color-coded orange or sometimes orange with a white stripe. These color codes help identify different wires for easy installation and troubleshooting.

In detail, to locate it, you’ll first need to remove the stereo from the dash. Most stereo systems can be removed using a stereo removal tool, but some may require you to disassemble parts of the dashboard. Once the stereo is removed, you’ll be able to see the bundle of wires at the back.

Within this bundle, look for the wire that’s either orange or orange with a white stripe. This is your illumination wire. Remember, it needs to be connected to the corresponding wire on your car’s wiring harness to operate correctly.

Keep in mind that the color of this wire on the wiring harness may be different depending on your car’s make and model. For this reason, referring to your vehicle’s specific wiring diagram is advisable.

Finding and correctly connecting processes can be a bit tricky, especially for those unfamiliar with car stereo systems. If you feel unsure at any point, don’t hesitate to consult a professional to avoid any potential damage to your car stereo system.

Car’s stereo

Illumination Wire on Car Stere: How to Connect

Connecting this wire is a crucial part of setting up your car stereo system. Here’s a detailed, step-by-step guide on how to connect this wire:

Before starting any electrical work in your vehicle, the first step should always be to disconnect the car’s battery. This ensures your safety and prevents any accidental short circuits during the process.

Next, to access the wiring, you’ll need to remove the car stereo from the dashboard. Depending on your car model, this might require a specific set of tools or simply a careful hand to avoid damaging any of the components.

Once you’ve removed the stereo, look at the back where you’ll see a bundle of wires. Among them, locate the illumination wire. It’s typically color-coded orange or sometimes orange with a white stripe for easy identification.

Now, turn your attention to your car’s wiring harness, which should be visible once the stereo is removed. Similar to the stereo, there will be an illumination wire in the harness as well. The color might vary based on the car’s make and model, so refer to the vehicle’s wiring diagram if needed.

After you’ve identified both these wires, it’s time to connect them. You can do this by twisting the ends of the two wires together and securing them with a wire nut. Additionally, you can use a soldering iron for a more lasting connection and cover it with electrical tape to ensure safety and prevent any shorts.

With the wires connected, you can reinstall the car stereo into the dashboard. Make sure all the other connections are also secure before continuing.

Finally, reconnect your car’s battery and turn on the headlights. This should cause the radio’s display to dim, indicating that your connection is correct. If the display doesn’t change, you might have to check your connections and repeat the process.

Remember, working with electrical systems can be tricky, especially for beginners. If you’re unsure about any of the steps, it’s advisable to seek professional help.

Car’s stereo installation

What Happens if You Don’t Connect the Illumination Wire

If you choose not to connect this wire, your stereo system will still work fine, but it won’t dim in conjunction with your car’s headlights. This might be a distraction, especially when driving at night as the brightness of the stereo’s display may be stark compared to the dimmed dashboard lights.

How to Fix if the Illumination Dimmer is Not Working?

If you’ve noticed that your illumination dimmer isn’t working, there are a few steps you can take to try and fix the issue.

First, you need to gather tools to fix it on your own. You’ll need a set of screwdrivers, wire connectors, electrical tape, and optionally, a multimeter to help you troubleshoot.

And start by turning off your vehicle to ensure your safety. Make sure the engine is off and take the keys out of the ignition before you continue.

To address the problem, you’ll need to identify the illumination wire. Consult the stereo’s user manual or a reliable wiring diagram to locate the specific wire responsible for controlling the dimming feature. This will help you determine the wire’s color and its position.

Now, it’s time to remove the stereo from the dashboard. The process may be different depending on your vehicle’s make and model. You might need to use a screwdriver or specialized stereo removal tools. It’s a good idea to refer to the manufacturer’s instructions or search for online resources tailored to your particular vehicle.

With the stereo removed, carefully inspect the wiring connections. Pay close attention to the connection of the illumination wire. Ensure it is securely attached to the correct terminal on the stereo. If you come across any loose or disconnected wires, proceed to the next step.

In this step, you use wire connectors to reattach any loose or disconnected wires firmly. Strip a small section of the wire insulation, insert it into the wire connector, and use pliers to crimp it tightly. Be sure to repeat this process for all the affected wires.

After reconnecting the wires, it’s time to test the connection and check if the illumination dimmer is working properly. Reassemble the stereo and dashboard components, but don’t fully secure them just yet. Turn on the car’s ignition and try adjusting the dimmer settings. If the dimmer responds correctly, move on to the next step. If not, it’s advisable to seek professional assistance, as there may be underlying issues.

Once you have confirmed that the illumination dimmer is working correctly, securely fasten the stereo and any other dashboard components that were removed earlier. Ensure that all screws and clips are properly tightened.

If the issue persists despite your efforts, you might consider additional troubleshooting steps. This could involve using a multimeter to test the voltage on the illumination wire, checking the fuse related to the stereo or illumination circuit, or reaching out to a professional for further diagnosis and repair.

Remember, if you feel uncertain about the steps or if the problem persists. So, it’s always best to consult a professional automotive technician.

 Seek professional assistance


While the illumination wire in a car stereo may seem small, it plays a big role in enhancing your driving experience. Knowing how to connect it properly and troubleshoot common problems can help you enjoy your car stereo to the fullest.


Does the illumination wire have to be connected?

While it’s not required to connect this wire for the car stereo to function, it’s highly recommended for the best user experience. If not connected, the stereo’s display will not dim along with the car’s interior lights, which can be distracting, especially during nighttime driving.

How do you know if your car radio has an illumination wire?

The easiest way to identify if your car radio has an illumination wire is to look at the wiring at the back of the radio unit. It is typically orange or orange with a white stripe. Additionally, your stereo’s user manual or wiring diagram should provide detailed information.

What color is the illumination wire?

The illumination wire is typically orange with a white stripe. In the wiring of a car stereo, the 12V battery wire is usually yellow, the accessory wire is red, and the dimmer can be identified by its orange color with a white stripe.

Additionally, the right-front speaker wires are commonly gray, the left-front speakers are white, the right-rear speakers are purple, and the left-rear speakers are green.