No Illumination Wire on Radio: What Should You Do?

If you hadn’t noticed before then it can be a surprise to find out that your car radio doesn’t have any illumination wires. After finding out, you are not sure whether to tap it or just leave it as it is.

So, what should you do in a no illumination wire on radio situation?

You can either tap into the constant or accessory circuits. Or you can also use cig lighter illumination circuits to tap the wire into it. If you still can’t find any options, then just leave it on its own or get an aftermarket adapter. Finally, you can get yourself a new radio altogether which has illumination wires built-in.

While those are some quick fixes, you might need to know more about illumination wires and how to solve these issues.

Let’s get started!

What Is the Illumination Wire?

Illumination Wire

The illumination wire on a car radio is a wire that is responsible for controlling the brightness of the radio’s display. When the headlights of the car are turned on, the illumination wire is activated, causing the display on the radio to dim so that it does not cause any distractions while driving at night.

The illumination wire is usually connected to the car’s wiring harness, which receives signals from the car’s lighting system. This wire is usually colored orange or orange with a white stripe, although the exact color may vary depending on the specific make and model of the car and the radio.

If you are installing a new car radio, it is important to properly connect the illumination wire to the car’s wiring harness to ensure that the display is properly controlled when the headlights are turned on.

If you’re also curious about what the TRAF button does on car radio, read from here.

How to Tell if Your Car Has an Illumination Wire or not?

You can tell if your car has an illumination wire or not by checking the car’s manual. If that does not seem satisfactory enough, you can look for the harness wire on the radio. Or you can also check via multimeter and see the voltage spike when you turn your headlights on.

While you might think that you don’t have an illumination wire on your car stereo but are you sure enough? If you’re not then here are the steps to thoroughly check whether you have an illumination wire on your car radio-

Check the Car’s Manual:

As mentioned before, taking a glance at your car manual can tell if you have an illumination wire installed or not. However, sometimes, the manual may not mention whether you have an illumination wire installed.

In such a scenario, you have to check it manual-ly! (pun is indeed, intended)

Look for the Wiring Harness:

Look behind the radio and check for a wiring harness that is connected to it. If there is a wiring harness, check to see if there is a wire that is colored orange or orange with a white stripe. This wire is most likely the illumination wire.

Use a Multimeter:

You can use a multimeter to test the wiring and see if there is a voltage change when the headlights are turned on. If there is a voltage change, then your car has an illumination wire. If not, you know the answer.

Why Do Some Car Radios Don’t Have Illumination Wires?

The main reasons behind not including an illumination wire in the car radio are cost-cutting, design elements, and compatibility issues. 

Find out more about that from the below discussion-


Illumination wires require additional components and wiring, which can add to the cost of manufacturing a car radio. To keep the cost down, some manufacturers may choose to omit the illumination wire.


Some car radio designs may not require an illumination wire. For example, if the radio has an LED display that is designed to be easy on the eyes at night, an illumination wire may not be necessary.


Not all cars have an illumination wire in their wiring harness. If the car does not have an illumination wire, there may be no reason to include one on the radio.

However, one good thing about illumination wire is that it has nothing to do with FM radio not working. Your FM radio will work seamlessly without having an illumination wire.

What Should You Do if the Car Has no Illumination Wire on the Radio?

If you don’t have an illumination wire, you can either force-tap it or leave it alone. Moreover, you can use an aftermarket adapter that can make your harness wiring usable with your headlights.

Illumination Wire on the Radio

Still, seems confusing enough? Well, here are the things you can do if you don’t have any illumination wire on your car radio-

Adjust the Brightness:

Most car radios have a setting that allows you to adjust the brightness of the display. Make sure to adjust the brightness to a level that is comfortable for you while driving at night.

Use Ambient Light:

If the radio is located near other interior lights in the car, such as the dashboard lights or overhead lights, adjust the brightness of these lights to match the brightness of the radio display. This will help reduce the contrast and make the display easier to see.

Use an Aftermarket Adapter:

Some aftermarket adapters are available that can convert the wiring in your car to allow for an illumination wire to be connected to your radio. These adapters may require professional installation, so make sure to consult with a car audio installer or mechanic before attempting to install one yourself.

Challenges of Using a Radio without an Illumination Wire

Similar to transmission not reaching far on CB radio, not having an illumination wire can be challenging. Let’s see what disadvantages you might face if you don’t have an illumination wire-

Limited visibility:

Without an illumination wire, the display screen of the radio will not light up, making it difficult to see the station, frequency, or any other information displayed on the screen. This can make it challenging to use the radio, especially in low-light conditions.

Increased distraction:

Drivers who use a radio without an illumination wire may be more distracted as they try to read the display while driving. This distraction can lead to accidents, as the driver’s attention is diverted from the road.

Difficulty in adjusting settings:

Without an illumination wire, it may be challenging to adjust the settings of the radio. This could include changing the station, adjusting the volume, or setting up presets.

Incompatibility with certain vehicles:

Some vehicles require an illumination wire to power the radio. Without this wire, the radio may not work at all or may not be compatible with the vehicle’s electrical system.

Can Illumination Dimmer be Used Instead of Illumination Wire?

In some cases, an illumination dimmer can be used instead of an illumination wire, but it depends on the specific radio and the vehicle in which it is being installed.

illumination dimmer

An illumination wire is a dedicated wire that is typically connected to the vehicle’s lighting circuit. That allows the radio to adjust its brightness based on the vehicle’s headlights being turned on or off. 

An illumination dimmer is a device that adjusts the brightness of the radio display manually, typically by turning a knob or pressing a button.

If the radio has a feature that allows it to adjust its brightness manually or via an illumination dimmer, then it may be possible to use an illumination dimmer. 

However, if the radio does not have this feature then you can’t replace your illumination wire with an illumination dimmer. So, all of it boils down to whether your car has support for illumination dimmer or not. If you don’t feel that way, make sure to contact a professional. 

Frequently Asked Questions (FAQs):

How Do I Fix the Illumination on My Car Radio?

To fix the illumination on your car radio, check the dimmer setting, the illumination wire, and the fuse. Make sure the dimmer setting is not too low or turned off, the lighting circuit is functioning properly, and the fuse controlling the radio’s illumination is not blown. If the issue persists, check the wiring for damage or consult a professional.

What is the Orange Wire on a Radio Harness?

In general, the orange wire on a radio harness is usually the “illumination” wire. This wire is designed to connect to the vehicle’s lighting system and provides power to the radio’s display and buttons. Allowing them to be illuminated when the vehicle’s headlights are turned on.

Can I Still Use my Car Radio if It Doesn’t Have an Illumination Wire?

Yes, you can still use your car radio if it doesn’t have an illumination wire. However, you may need to adjust the brightness manually, which can be a distraction while driving.


To conclude everything, having no illumination wire on radio is not that much of a big deal. However, getting it soldered with your car stereo can raise the overall experience of driving and listening to the radio at night.

So, if you really want to use your illumination wire with your car radio, you now know what to do!


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