The Ins and Outs of Identifying Positive Headlight Wire

Having a proper set of headlights that are working is essential for safe night driving. Knowing how to identify the positive and negative wires a headlight has is a major part of the maintenance process. Having a good understanding of which wire is the positive and which is the negative is important so as to maintain the polarity of the headlight.

In this article, we shall be discussing the importance of having the correct headlight polarity alongside how to safely identify the positive headlight wires and the necessary safety precautions that will help you repair and replace your headlights.

Why do headlights have three wires?

Headlight wires provide power to headlight bulbs and if it becomes faulty, you can replace them at home. The wire is connected to the base of the headlight bulb and to the power distribution board in the engine. There’s no need to remove any part in order to replace your headlight wire although the process can vary depending on the model of your vehicle. The replacement process could take about half an hour. 

Therefore these three wires which aid the headlight connection are very important for lighting your path at night. The information about the wires and their distinct colors is explained in the next heading. 

What are the wire colors of a headlight wire harness?

There’s a  popular belief that these wires have specific colors across all vehicle types which is a half-truth, there are no standard colors of headlight wiring for vehicles. But then there are different color codes for different headlights. The color can vary depending on the model of the car. The best way to detect the right wiring colors is to test the wires with a multi-meter or voltmeter. If this is something you cannot do yourself, seek professional help.

 How do identify a positive headlight wire?

Headlights have low, and high beams and ground that are represented by different colors. Mostly, the negative wire is on the right side which is opposite to the ground while the low beam is in the middle slightly higher than the other two for an H4 headlight. This scheme is followed in other headlight plug designs. 

Removing the plug that is connected to the headlight is the simplest way to identify a positive headlight wire. Here are a few steps:

•  Set your meter to a 12- Volt DC.  make sure that the leads are properly connected to the meter
• Turn your headlights on and dim the lights. 
• Connect the black test lead to your vehicle frame having no rust or paint.
• Connect the red test lead to one of the three holes of the plug that was disconnected from the headlights of your vehicle.
• The meter should read about 12-13 volts. If this shows, that means it is a positive wire. 
• If you don’t see any reading on the meter, that means the wire is negative and on the high beam side of the headlight. 

Safety precautions for handling headlight wires

When a 12V wire is exposed, even if it is protected from touching the chassis, this could also cause a short. Therefore, always wrap the wires using electrical tape. Constantly check the electrical connector at the back of the headlight for any damage or looseness. Lastly, don’t hesitate to replace a burnt bulb.

Conclusion 

When your plug is corroded, melted or even damaged, you may need to replace the plug with a new one and to replace the headlight wires, you must be aware of the different headlight wire color codes to replace the headlight wiring.

For the record, it’s been said that black wires are for ground, red for high beams and yellow for low beam wires which is the positive wire.