What is a Headlight Module?

A headlight module is a device that regulates the function of a vehicle’s headlights. It usually consists of a light sensor, a switch, and a control unit.

The module may also include a relay to control the headlights. It is usually located near the headlight itself, and it may be integrated into the headlight assembly or installed separately. In addition, the module may be controlled by the vehicle’s onboard computer, a separate controller, or the switch on the dashboard.

How Does a Headlight Module Function?

Headlight modules are responsible for providing power to the headlight. They are typically located in the engine bay, and they use a series of relays to provide power to the headlights. The light sensor detects when it is dark outside and activates the headlights.

The headlight switch sends a signal to the headlight module, which then turns the headlights on or off while the control unit supervises the operation. The headlight module may also contain a fuse, and it protects the headlights in the event of excess power input for turning the headlights on and off.

Types of Headlight Module

Based on the working material, headlight modules are common of three types:

LED Headlight Module:

The LED headlight module is the least expensive headlight module on the market. It uses light-emitting diodes to produce a bright, white light.

HID/Xenon Headlight Module:

The HID headlight module is an expensive option, but it is very efficient. It uses high-intensity discharge bulbs to produce a bright light that is very similar to daylight.

Halogen Headlight Module:

This module is designed to be used with xenon headlights. It is a simple and direct plug-and-play installation that requires no changes to your current headlight setup.

Headlight modules can also be categorized into six types depending on their specific purpose.

Headlight Level Control Module:

This module adjusts the height of the headlight beam in response to changes in the vehicle’s suspension.

Headlight Aiming Control Module:

This module controls the horizontal aim of the headlight beam.

Headlight Cleaning System Control Module:

This module controls the headlight cleaning system, which helps keep the headlight lens clean.

Headlight Washer Control Module:

This module controls the headlight washer system.

Headlight Dimming Control Module:

This module dims the headlight beam when the vehicle’s headlights are turned on.

Headlight Intensity Control Module:

This module receives a signal from the headlight relay and controls the intensity of the headlights accordingly.

Features of Modern, High-Quality Headlight Modules

Switch Modulation:

You can toggle the headlight modulator throughout the daytime, but DOT regulations do not allow this function to be used at night. So, modern headlight modules come with a feature that allows you to activate or deactivate the modulation by just moving your car’s high or low beam switch in the opposite direction and then returning to its initial setting within a second.

Automated Modulation:

Modern headlight modules are designed to automatically switch your car’s headlights on and off at appropriate levels depending on the information available about the lighting in your surroundings.

Switching Modes:

Modern headlight modules have two stages of modulation that are completely DOT certified. The default setting is “Max,” but you can simply change it to “Min” or back to “Max” by pressing your horns twice in a second.

Heads-Up Warning System:

A high-quality headlight module may feature a green cable on the connector that can be linked to your car’s horn to provide a visual warning for the horn’s auditory signal. If the module is deactivated, activating it will force your headlights to fluctuate for about 3 seconds before returning to a steady state. An activated module will toggle the headlights between min and max.

Backup Headlights:

Modern headlight modules regularly check the headlight bulbs in your car. If one of the bulbs fails, the backup bulb will be switched on immediately. The backup headlights will only be switched on once when you start your car. Furthermore, you will be unable to use the flawed bulb until it has been fixed or replaced.

Heat and Voltage-spike Resistant:

High-quality headlight modules can resist heat buildup in the headlight assembly. Even at a steady maximum illumination of 130 watts of rated output, it can operate flawlessly with only a little rise above the room temperature. These modules can also prevent voltage bursts during the ignition of the engine or the charging of the batteries.

How to Install a Headlight Module

If you see that your car’s headlight beams have become dim or if the headlight beams are not illuminating the roads properly, then you will need to replace the headlight module. In most cases, changing the module fixes the problem. Installing a new headlight module is very easy, and this section will show you just how to do it.

  • First, open the hood and disconnect the negative battery terminal.
  • Unplug the headlight connector from the headlight bulb.
  • Remove the headlight bulb from the headlight assembly and unplug the module from its electrical connector.
  • Connect the new module in reverse order and secure it in place with the retaining clips.
  • Reconnect the headlight connector to the headlight bulb and reinstall the headlight bulb into the headlight assembly.
  • Close the hood and reconnect the negative battery terminal.

Final Notes

Headlight modules are generally very cheap to get. It usually costs around $100. And a headlight module that has been damaged by water or has worn out due to its age typically costs around $200 to $300 to replace. Before purchasing or replacing a headlight module, you should check the build and model of your car. Older cars didn’t have a relay or switch-style headlight modules. Philips, Sylvania, GE, and Osram manufacture OE-grade headlight modules. You can also buy it from the aftermarket.

Leave a Comment