How to Locate the Ignition Wire for your Car Stereo [2 METHODS]

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Where Do You Find Ignition Wire?

You can locate the ignition wire for your car stereo in two ways. The first is checking your vehicle’s radio diagram. The second involves testing the different wires running through your radio using a multimeter or test light to separate the stereo’s ignition wire from the rest.

Things You Will Need

  • Wiring diagram that provides an illustration of the wiring for your vehicle
  • A multimeter or test light

Finding Ignition Wire Using the Wiring Diagram

If you choose to find the ignition wire for your car’s stereo using a wiring diagram, you need to follow the steps below to accomplish your objective.

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Step 1: Find Your Radio Ignition Wire’s Make, Model, And Year Using Radio Ignition Wire Diagram

There is no easier way to find the ignition wire for your car stereo than searching for it in an illustration of the wiring for your car. You can begin your search by tracking down the specific make, model, and year of your radio ignition wire. This is important because wiring can change in some cars every time a new model is released.

Step 2: Match Your Findings on the Diagram with the Wiring on Your Vehicle

Once you have the right radio ignition wire diagram with you, you need to try and decipher it. After this, compare what you see on the radio diagram to what you see in your car stereo. This will allow you to find the ignition wire for car stereo. That’s all there is to it.

Finding Ignition Wire Using Multimeter or Test Light

When using a wiring diagram to locate your car stereo’s ignition wire does not help, I would suggest you try this next method to get things done.

Step 1: Remove the Radio from the Housing and Connect the Multimeter/Test Light for Testing

The first step is to remove the radio from its housing in order to access the back wires. Once this is done, connect the multimeter or test light with the clamp for testing.

Step 2: Understand the Purpose of Each Wire Running Through the Radio

You may notice red, yellow, and black wires in your car stereo. These are referred to as power wires. The main purpose of power wires is to power up your car stereo.

The ground is the black wire that runs through the receiver. The permanent power wire is the yellow wire that emerges from the radio wire. The red wire, which is usually an ignition wire for the car stereo, is also likely present. You will need to test the wiring to be certain because there may be two red wires: one for the ignition and another for the dimmer.

Step 3: Begin the Testing Process by Checking the 12v Wire and Measuring for Continuity

Set your multimeter to the appropriate level, then connect the ground lead to an established good ground and each wire in the speaker wire with the other lead.

The constant 12V wire also referred to as the memory wire, can be found when the multimeter shows roughly 12V. In most aftermarket head units, it is the yellow wire.

Ground wires are generally black, but don’t take this for granted. You can confirm that the black wire is the ground by connecting the multimeter to an established good ground, and then checking each wire in the car stereo harness for continuity. The ground is the one showing continuity.

Step 4: Check for the Dimmer and Ignition Wires

There are a few other wires to check in order to locate the ignition wire. Start the engine and make sure the headlights and dimmer are turned all the way up. With the probe, check to see if both wires are reading 12 volts or higher.

Turn the dimmer down to see which one has changed. The dimmer wire, if your audio system has one, will display a different reading. Hence, naturally, the other one is the ignition wire for your car stereo! Label them immediately so you don’t forget which one is which.

Video on how to find ignition wire for car radio

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