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HomeTips & GuidesUniversal headlight Switch Wiring diagram: Making Repairing and Replacing the Headlight Switch Easier

Universal headlight Switch Wiring diagram: Making Repairing and Replacing the Headlight Switch Easier

AboutUniversal headlight switch wiring diagram: The headlight switch is an essential component of any vehicle, allowing you to operate the headlights. 

If the switch stops working, driving in low-light conditions or foggy situations is difficult.

So, always keep your headlight switch in working condition. Get help from this article, which tells you about the headlight switch, the reasons for its failure, and its repairing and replacement tactics.

Headlight switch understanding

A headlight switch, or dimmer switch, is an electronic switch that controls your vehicle’s headlights and functions. 

You can find them on the steering column in combination with the switch lever. You can also find them as buttons or knobs mounted on the vehicle’s interior.

As knobs mounted on the dash

The switch mainly controls the electricity flow to the headlights. When you turn the switch ON, electric current flows through the wires and reaches the headlights, activating them. As a result, you can see your front in low-light conditions. 

The switch of modern vehicles also controls additional functions like high beam lights or fog lights. You need to either push or twist the knob to activate these lights.

How to use the headlight switch?

Take the knob type, for example. The driver controls the manual headlights control. 

In the headlight switch, the first position is running lights. When you twist the knob to this position, running/tail lights illuminate. 

You use these lights in dusky and foggy terrains.

When you twist the knob further, you select a setting that allows the illumination of running/tail lights and headlights simultaneously. 

If you keep the knob in this position, the headlights remain On until the ignition is turned ON. 

As soon as you turn off the ignition, headlights also turn off to save the battery life. 

You can use headlights while you are driving at night in low-visibility conditions.

Besides all these, a high beam feature is helpful for drivers on open highway trips. 

As these lights have higher trajectories, turning them off when a vehicle is approaching from the opposite side is advisable to not impair the other driver’s vision. 

You can activate the high beam lights by pushing the left control lever forward. 

As you push, there will be a click, and the instrument cluster will slow a blue headlight symbol. 

When you push the lever forward, the switch will return to its normal position, turning off the high beam control lights.

You can also control the brightness of the instrument cluster through a headlight switch. It can be present as a thumbwheel adjacent to the main headlight switch control. 

In addition, when the thumbwheel is at the max position and reaches the travel end, you will feel a lick. This turns on the dome lights, allowing the driver to light up the passenger compartment.

Universal headlight switch wiring diagram:

(The switch uses two power supplies; one is for the headlights, park lights, dash and dome lights, and the other is for the tail lights.)
To tail lights Tail light feed From fuse block.
To headlights through a dimmer switchBattery Feed From circuit breaker
To dome light
To dash lights through a fuse
To park lights

Caption: GM headlight switch wiring diagram 

Depending on the model and make of the vehicle, there may be different types of headlight switches. In some vehicles, you will find stand-alone switches that only operate parking lights and headlights. On the other hand, some switches are combined with the turn signal switch.

Working of the vehicle headlight circuit:

In some vehicles, the headlight switch transmits a 12-volt low-current signal, turning on the headlight relays.

In this relay system, the switch receives the 12-volt power supply, sent to the headlight relay control when the headlights and parking lights are turned on. 

As a result, the relay turns on and sends power to the headlight on a high-current circuit. The presence of a relay prevents the premature failure of the switch.

On the other hand, some vehicles also provide ground to this relay or a 5-volt low-current signal to the body control module. 

In this system, the body control module does most of the work. The switch gets a 5-volt current from the control module. 

When you turn on the parking lights or headlights, the switch returns the signal to the body control module. 

With this, the body control module directly controls the headlights relay or the headlights.

Hand-adjusting car headlight control switch

Hand-adjusting car headlight control switch

Should you repair or replace the headlight switch?

It’s not surprising that with use, you can face some issues with the headlight switch. What would you do: replace or try to repair the switch?

Reasons why a headlight switch fails:

  • The headlight switch stripped badly, not allowing headlights to turn ON.
  • Switch getting stuck in one place until you remove it manually.
  • Corrosion due to water.
  • Wear down with use.

When the headlight switch goes wrong, you have two options: replace or repair.

Go for repair only if you have experience repairing the headlight switch; otherwise, it’s easy to replace it.

On the other hand, repairing a headlight switch is a challenging task. The wiring of the switch varies according to the year and model of the vehicle. 

Even if you know the wiring, removing the switch and checking the wires and connectors to identify the issue is not easy. 

You may unknowingly do wrong things, like losing small components or hardware. Sometimes, it is also possible that you cannot fix things back together.

To repair the headlight switch successfully, you must have

  • experience and knowledge of the wiring
  • A specific wiring diagram
  • Knowledge of headlight switch and its components

Universal headlight switch wiring diagram: Replacing a headlight switch

Replacing a switch is always cheaper. The switch costs you between $70 and a few hundred dollars. 

Buying an OEM switch would be a better decision as they are specifically designed for your car model. Also, it will come with all the components and hardware you need.

However, before you pick a replacement switch, confirming the vehicle’s year, model, and make is better.

If you are buying a custom headlight switch, you also need to conform to the mounting type and dimensions of the switch. 

Our custom wiring harnesses can be plugged directly into any headlight switch. Also, for easy wiring, wires have specific color coding.

Universal headlight switch wiring diagram: How can you replace a headlight switch:

First, look for the tutorial specific to the model and make of your car. You can get it from Google or YouTube.

Once you have the tutorial, you can follow this process for the headlight switch lever replacement:

  • Disconnect the battery and the car connectors
  • Next, disconnect the steering wheel and remove it
  • Now, remove the panel of the steering column
  • Replace the switch using the tutorial
  • Put everything back in the order opposite to that of removal


If you don’t have much knowledge about the headlight switches, it’s good to buy a new one and get it replaced. 

Get help from Cloom in replacing the new switch or updating the headlamp system. We deal in all wiring harnesses and cable assemblies associated with automotive applications.

Our professionals can also guide you in choosing the pigtail wiring harness according to your vehicle’s make, model and year.

I am Lillian Yang, having been a sales manager for over 10 years.

I have received many positive reviews from customers. They have praised our excellent service, on-time delivery, and high-quality cable assemblies.

For your projects, please provide cable assembly files/images/smples, etc., so that I can send you a quotation within 24 hours.

Contact me now and let’s get started on building your wire harnesses!

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