How To Identify Subaru Intermittent HID Headlight Issues

The Subaru HID system is a great feature, but it can be frustrating when it doesn’t work. Fortunately, there are several reasons why one or both of your Subaru HID headlights may not work, and many are fixable without replacing parts.

Check the Headlight Relay

The headlight relay is responsible for distributing power to your headlights, so it’s an excellent place to start when you’re trying to find an intermittent headlight issue. To test the relay, remove it from its mounting bracket and plug a new one into its socket. Then turn on your headlights—if they come on, you know that the relay was not the problem.

If this doesn’t fix your problem, you’ll need another way to check whether there’s corrosion or a bad connection in your wiring harnesses (which can be tricky). You could also try cleaning up any corrosion before installing a new harness; check out our guide here for more information on how to do it yourself!

Check the Control Unit

If you’re still experiencing intermittent headlight issues, it’s time to check the control unit. If you’ve replaced all the potential culprits listed above and the issue persists, this may be the problem.

A faulty control unit can cause several intermittent problems with your Subaru’s headlights, including:

  • Flickering lights
  • Lights that turn off and on randomly
  • High beams are always on (or not working at all)

Check the Fuses

The first step in diagnosing your Subaru intermittent HID light issues is to check the fuses. The fuse box you’ll need to check can be found in three places: under the dash and behind the glovebox, under the hood (in front of the driver’s side air filter housing), and passenger’s side footwell storage compartment.

Check for a Blown Bulb

If the light is out, you should check the fuse first. If it’s blown, you’ll need to replace it by locating the appropriate model and size in your Subaru’s fuse box.

Next, check for a blown bulb. You can do this by removing one of your headlight covers and shining a flashlight into the back of it (make sure you have gloves on!). If one or both bulbs are broken or cracked, they need replacing before they can be used again. To do so, push them in until they snap back out wholly—they should come right off with no force required if they’re good ones!

You should also check other parts inside your headlight assembly: ballast modules, igniters, wiring harnesses, control units, relays (though these may not work with intermittent issues), DRL Modules, and fuses.

Check the DRL Module

The DRL module is located behind the headlight. It is a small black box with a connector. It is connected to the control unit and is responsible for the DRL, high beam, and low beam functions.

To check whether there are any malfunctions in the DRL module, turn on your vehicle ignition and open up the door or hood of your car. Locate the headlights with halogen bulbs on both sides of your vehicle’s front end; they are usually yellowish-white in color and shaped like long slits with rounded edges (this will vary depending on which model Subaru you own). Grasp each light firmly but gently (you don’t want to break anything), then pull upwards towards yourself as if trying to remove it from its housing as shown above in Picture 1 below:

Check for a Broken Ballast

Ballasts are the part that heats the xenon gas, so they get hot and are often broken. If you have a fractured ballast, it will need to be replaced. The ballast is not easily accessible or replaceable. It can only be accessed if you remove the entire headlight assembly, which takes several hours and requires special tools.

Check for a Broken Igniter

It is essential to check the igniter because it is the most common cause of HID failure. The igniter is a tiny glass tube that heats up and produces the light in your headlight. It is located in a ballast, which controls voltage and power to the bulb.

The color of an igniter may vary depending on your Subaru, but typically they are either green or yellow. The outer part of an igniter looks like a small lightbulb with no filament inside it—it’s completely hollow.

It’s important to note that this part is fragile and can break easily if dropped or bumped against something complex (like a wall). However, even if yours doesn’t appear damaged yet if you’re experiencing flickering lights from your Subaru HID system, it could be time for some new ones!

Tips and Tricks

This article has provided several tips and tricks for identifying the source of your Subaru HID headlights not working. If you’re still experiencing issues after trying all these steps, we recommend you schedule a service appointment for further diagnosis.