How to Determine Harley Tail Light Wire Colors

The taillight is an important safety feature of your Harley Davidson motorcycles. It highlights the edges at the rear side of your motorcycle.

Thus, drivers from your back can know that you are in front of them at a distance. Therefore, the taillight goes a lot to ensure your safe driving. However, when it starts malfunctioning, you need to change it, and that’s when knowing the wire color becomes important.

Usually, the taillight of Harley Davidson has a blue color. Thus, you must work with the blue wiring when the taillight needs replacement. But what if you don’t know where the problem is and need to check the wiring for the turn-left signal, brakes, or ground? Don’t worry! We will also answer the wire colors of these parts of your Harley Davidson. We will show you how to determine Harley Tail Light Wire colors, Harley Davidson tail light, brakes, and ground and turn signal lights.

Harley Tail Light Wire Colors

What Is The Harley Davidson Tail Light Wire Color?

What Is The Harley Davidson Tail Light Wire Color

If you look closely at the tail light of your Harley Softail, Touring, or Road King models, you will see that the taillight is connected to the blue wire. However, it has no additional coating, unlike the Yamaha motorbikes.

Thus, you should easily identify the wiring issues and color of the taillight to change or repair it if need be. You should no longer have any problem identifying and replacing the taillight wiring. However, you might be keen to know the wire colors of the brake lights, ground, and turn signals.

So, here’s the answer for you. The following table will describe the wiring color of your Harley Davidson’s essential lights.

Component Name Wire Color
Taillight Solid blue color
Left Turn Signal Purple
Right Turn Signal Brown
Brake The red color also has a yellow stripe
Ground Black color

Now you should understand what colored wire you need to work with to repair which component of your Harley motorcycle. However, if you still find it difficult, we will show you how to determine the wire color of the taillight and other ones in the following section.

How To Determine Harley Tail Light Wire Colors- Explained

How To Determine Harley Tail Light Wire Colors- Explained

It is important to locate the tail light wiring harness. This can usually be found under the rear fender or along the motorcycle’s frame. Once located, carefully inspect the green wires and identify the different colors present. Common wire colors for Harley tail lights include red, black, green, yellow, and white.

To determine the specific functions of each wire, it is advisable to consult the motorcycle’s service manual. The manual will provide detailed wiring diagrams indicating the various wire colors and their corresponding functions. This information is invaluable in understanding the electrical system of the tail lights. It is worth noting that different Harley late models may have slight variations in wire colors. Therefore, referring to the specific manual for accurate information is crucial.

Determining the wire color of your Harley Davidson is straightforward. Also, you can follow similar steps to know the wire colors of your brake wire lights and other electrical components. So, let’s dive deep into the steps on how to determine Harley Tail Light Wire Colors.

Step 1: Secure Your Bike

Secure Your Bike

You must place your bike securely when looking at your Harley’s wire colours. Ensure that the place is even and the bike doesn’t wobble. Also, it should be clean because you may need to lean on the ground to look at the bike’s wiring. Lastly, the place should have enough natural or artificial light so that you can look at the different wire colors easily.

Step 2: Observe The Wire Colors

When placing the Harley bike securely and ensuring proper lighting, it’s time to start observing the wire colors, orange wire. You should keep a screwdriver and an adjustable wrench ready in your hand because you will need to disassemble a few exterior parts to access the wiring system. The steps include the following:

  • You can begin from the rear end of your Harley motorbike. Since you must access the wirings, you might have to disassemble the rear cowling using a screwdriver. However, the easiest way to access all the wiring is to remove the passenger seat from the top of your Harley bike.
  • Once you have removed the passenger seat, you may look at the wires easily. As you start observing the wire colors, you can identify a particular pattern for each type of wiring. Some wires will connect with the hub, and others might lead through the hubs.
  • You can take a small piece of paper and a pen to take note of the actual wire colors. Also, understand that every motorcycle company has unique color codes for the different wires for easy identification. Thus, the wire colors of Harley will be different from those of KTM or Honda.

Step 3: Figure Out The Color Of The Ground Wire

Figure Out The Color Of The Ground Wire

When you confirm the colors of the ground wire, the maximum task you will be done. The ground wire is a single-wire connector with every brighter light of the Harley bikes. This is common wiring for all the light, and Harley uses solid black color for this ground wire.

Now, it’s time to identify the other wire colors since you no longer need to consider the ground wire. So, let’s turn or focus on identifying the colors of the other wires.

Step 4: Identify The Brake Light And Turn Signal Light Wire Colors

Identify The Brake Light And Turn Signal Light Wire Colors

You must find the wire colors for the turn signal and brake lights. You should look closely at the brake light to see which colored wiring is coming out. Also, the easiest way to find the turn signal positive wire color is to look for the wire except for the ground wire. Leave the ground wire and find the other wire connections to the turn signal wire light. It is the turn signal positive wire. Now, you should note down the color of this wire.

Also, you should identify the wire color for the turn right and turn left lights. You need to look at the wire colors leading right to the main wire harness of your motorcycle. In Harley Davidson, the colors of the turn left and turned right lights will be purple and brown, respectively.

Step 5: Recognize The Color Of The Tail Light Positive Wire

Finally, you can easily recognize the color of your Harley taillight. For this, look at the wire of the license plate and its color. There will be another wire connected to the license plate wiring. However, it’s not the ground wire. Thus, except for the ground and attached wire, this is the tail light positive wire. For Harley, it will always be in solid blue color.

A Key Note: Crosscheck The Wires

A Key Note - Crosscheck The Wires

Your task of identifying the wire colors for different lights of Harley Davidson doesn’t end here. You must crosscheck the wire colors before ending the session with the final notes. The steps to crosscheck the lights are easy.

  • Firstly, disconnect all the wires from the battery
  • Now, start connecting the wires one by one with the battery.
  • You should see that the corresponding light is illuminated

Now, you know which wire has led to which light from the battery.

Common Wire Color Codes For Harley Tail Lights

Common Wire Color Codes For Harley Tail Lights

When wiring of Harley tail lights, understanding the common wire color codes is essential. The power circuit of the tail light assembly is crucial for its functioning. The blinker wires are usually found in yellow, indicating their purpose. Different color wires are used to distinguish the current wires and lighting wires. These wires play a significant role in ensuring proper lighting and the functionality of the tail lights on your Harley.

When determining the wire colors for Harley tail lights, there are some common codes to be aware of the tail light function. These color codes can vary depending on the specific model and year of your Harley, but here are some general guidelines to help you out. Know your Harley model and year as wire colors may vary.

  • Red Wire: brake lights.
  • Black Wire: ground connection.
  • Yellow Wire: left turn signal.
  • Green Wire: right turn signal.
  • Brown Wire: tail lights.
  • White Wire: license plate light.
  • Blue Wire: auxiliary functions or special features.
  • Refer to the owner’s manual or wiring diagrams for accurate wire color codes.

Remember that these color codes are not universal and may vary between Harley models and years. It is always best to consult a wiring diagram or your motorcycle’s manual for accurate and specific information regarding your particular bike.

Harley Davidson Wiring Diagram – Reference

Harley Davidson Wiring Diagram – Reference

Component Function
Battery Supplies electrical power
Ignition switch Controls power to the system
Starter relay Engages the starter motor
Starter motor Turns the engine to start
Ignition coil Converts low voltage to high
Spark plug Ignites the fuel-air mixture
Alternator Generates electrical power
Headlight Provides illumination
Turn signals Indicates the direction of turning
Brake lights Signals braking action
Horn Produces sound for signaling

The color of the tail light wire on a Harley Davidson motorcycle wiring can vary depending on the specific model and year of the bike. However, in most cases, the tail light wire is either red or black. The red wire is typically the positive wire that connects to the tail light bulb, while the black wire is the ground wire.

It’s important to consult your motorcycle’s owner manual or wiring diagram to determine the exact colour coding for your specific model. If you are unsure about working with electrical wiring, it’s always best to consult a professional or seek assistance from a knowledgeable mechanic to ensure proper installation and avoid any potential damage to your motorcycle’s electrical system.


Are you clear on how to determine Harley tail light wire colors is solid blue? Once you remove the passenger seat and identify the ground wire color, you can easily find the wire color for the taillight. It will be useful if you ever need to replace the wire due to faults or damages.

Also, you may accomplish the wire replacement at home with some mechanical and electrical knowledge on your Harley Davidson. Consulting the owner’s manual or contacting a professional mechanic can provide further guidance and assistance. By understanding the wiring system and following proper safety precautions, you can successfully install or troubleshoot your Harley tail light without any hassle.

Frequently Asked Questions:

What Color Are The Wires On A Motorcycle Tail Light?

The color of the wires on a motorcycle’s tail light can vary depending on the make and model of the motorcycle. It is best to consult the owner’s manual or a wiring diagram specific to your motorcycle to determine the correct wire colors for the tail light.

What Are The Colors Of Tail Light Wiring Harness?

The colors of the tail light wiring harness can vary depending on the make and model of the vehicle. However, common colors used for tail light wiring include red for the brake lights, yellow or amber for the turn signals, and white wire or black for the ground wire.

What Are The 3 Wires To A Tail Light?

The three wires to a tail light typically include the ground wire, usually black or brown; the brake light wire, usually red; and the running light wire, usually green or yellow.

What Are The 4 Wires On A Tail Light?

The four wires on a tail light typically correspond to the following functions: ground, running or parking lights, brake lights, and turn signals. The specific color coding of the wires may vary depending on the vehicle’s make and model.

What Is The Color Code For 4 Wire Plugs?

The color code for 4 wire plugs can vary depending on the application. However, a common color code is black for hot, red for hot, white for neutral, and green or bare copper for ground.

2 thoughts on “How to Determine Harley Tail Light Wire Colors”

  1. Have a 6 wire plug that had to be cut 2001 sportster to marry a 8 wire no plug bullit bar has 4 black 2 purple 2 blues the wires from the stock rear harness has 1blue 1 black 1 orange 1 purple 1 red 1 brown having difficulty matting the wires can you advise

    • It sounds like you are trying to connect a 6-wire plug to an 8-wire harness on a Sportster motorcycle. From the information you provided, it appears that the 6-wire plug has 4 black wires and 2 purple wires, while the 8-wire harness has 2 blue wires, 4 black wires, 1 orange wire, 1 purple wire, 1 red wire, and 1 brown wire.

      To properly connect these wires, you will need to identify which wires on the 6-wire plug correspond to which wires on the 8-wire harness. This can be done by using a circuit tester or a multimeter to test the continuity of the wires and identify which ones are connected to the same circuits.

      Once you have identified the matching wires, you can splice them together using wire connectors or soldering. Make sure to properly label the wires to avoid confusion, and double-check your connections before turning on the motorcycle to ensure that everything is working properly.

      If you are unsure about how to properly connect the wires, it is always best to seek the assistance of a qualified motorcycle mechanic or electrician to avoid damaging your motorcycle or causing a safety hazard.


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