Subaru Crosstrek Headlights Burning Out? (11 Common Causes)

The Subaru Crosstrek has many fans because it’s affordable, drives like a car, and can also easily take on dirt roads when called upon.

Like any other vehicle, its headlights need to be replaced every few years.

But if your Crosstrek’s headlights keep going out after only a few months, this article may help you find a solution.

Why Do My Subaru Crosstrek Headlights Keep Burning Out?

Frequent headlight failures in a Subaru Crosstrek are often caused by improper handling of the bulb during installation. Other common reasons also include wiring issues, electrical problems, corrosion, excess moisture and using aftermarket bulbs.

If your Subaru Crosstrek’s headlights are constantly burning out, this list of common causes can help you troubleshoot the problem. 

1. Improper Handling of the Bulb

Holding replacement bulbs with your bare hands during installation is a common cause of premature failure.

This only applies to the first generation and lower trim levels of the second gen Crosstrek which use halogen headlights. Higher trim levels of the second gen model come standard with modern LED headlights.

Halogen bulbs operate at really high temperatures. When you hold them with your hands during installation, you can transfer oils, sweat and other contaminants onto the glass bulb.

When you switch on your headlights, the oil on the bulb becomes hotter than normal and will eventually cause the glass to crack and even explode in some cases.

This issue is prevalent in all vehicles equipped with halogen bulbs, and therefore, not unique to the Crosstrek.

To avoid contaminating the glass, wear clean gloves or at least use some clean paper towels whenever you handle it outside of its packaging.

The bulb and the filament inside is also fragile, so try not to drop it or be too rough with it during the installation process.

If you think the bulb is already dirty or contaminated, you can always wipe it down with rubbing alcohol then let it dry out completely prior to installation.

2. Using Aftermarket Bulbs

Higher output bulbs that produce brighter light don’t last as long as the OEM headlight bulbs.

Brighter halogen bulbs produce more heat so their filaments burn out quicker. Similarly, cheaper bulbs also have lower life spans because of the lower quality materials that they use.

Here’s what one user on ClubCrosstrek.com had to say about Sylvania Silverstar bulbs which are very popular:

“They are nice for being a halogen bulb. Just be prepared to change them out once a year or so as they tend to burn out quickly.”

The stock headlight bulbs usually have a ‘Long Life’ label on them and are often rated for 1,000 hours or more while replacement bulbs might only be rated for a few hundred hours.

If you’re already using OEM bulbs, but they still keep burning out in just a few months, you might want to grab a set from your nearest Subaru dealer to make sure you’re getting the original part.

3. Bulb Connector Issues

Damaged or worn-out headlight connectors can often lead to frequent bulb failures.

Headlight bulbs will have shorter lifespans if they’re:

  • Constantly turned on and off
  • Not getting the right voltage
  • Operating at higher temperatures

The Subaru Crosstrek’s bulb connectors have a plastic locking mechanism which can wear out over time which causes it to become loose. 

As you’re driving, the vibrations and shaking will make the electrical contacts weaker and may cause the bulb to intermittently turn off, flicker or look dimmer than normal — which ultimately shortens its lifespan.

The constant temperature changes or heat cycles also weakens the bulbs components.

Additionally, the intermittent electrical connection can cause sparks or electrical arcs. These often result in voltage fluctuations that can damage the bulb. If there’s too much voltage or current running through the connector, they can also start melting.

Here’s how one owner on the ClubCrosstrek.com forum described their experience:

“I spent an hour on this issue to figure out my right hand wiring harness was not tight and the bright bulb connector has a short in it.”

A brittle, cracked or melted connector should be replaced immediately. Bulb connectors are fairly cheap and can be easily spliced in after cutting off the old ones.

If the plastic locking tabs are broken, you can insert some rubber or foam on the sides to make it fit snugly again.

You should also check inside the headlight connector for corrosion or dirt, then clean it out using a toothbrush, a screwdriver or some sandpaper.

4. Wiring Problems

Worn out insulation and frayed wires can cause the headlight bulbs to burn out prematurely. 

There are several ways that the insulation can become stripped: 

  • Deterioration over time 
  • Getting caught or pinched on body panels
  • Chewed up by rodents 

When the insulation is compromised, the wires can create a short circuit when they touch against each other or any metal part of the chassis. 

Even if the insulation looks normal, the copper wires inside can break over time, especially if they are bent or stressed repeatedly. If the wires are frayed and aren’t making a good connection, the lights can turn on and off repeatedly with just a bit of vibration, which shortens the life of the bulb.

Frayed wires also have higher resistance and produce more heat because they can’t adequately handle the current that’s flowing through them. This results in voltage problems, as well as heat issues, which aren’t good for the bulb.

Identifying wiring issues can be difficult without the help of a mechanic or an auto electrician. However, you can visually inspect the wiring for visible breaks, fraying, or missing insulation, as well as evidence of burn marks or melting, which are indicative of wiring problems.

If there is no visible damage, turn on the headlights and verify if any of the wires become excessively hot to the touch. In cases where there are broken strands of wire, the intact wires may be carrying a heavier load, leading to an increase in heat generation. Fortunately, replacing the headlight warning harness is fairly simple and affordable.

You should also check the ground wires connected to the chassis for potential damage such as corrosion or loose connections, as this can cause a range of electrical problems. 

5. Corrosion

Corrosion in the headlight bulb connector or other parts of the lighting system’s wiring can cause electrical issues that reduce the lifespan of the headlight bulbs. 

Corroded wires and electrical contacts don’t conduct electricity very well and might cause your headlight to become dim or intermittently flicker. 

It also causes higher resistance which generates more heat, lowering the lifespan of the bulb.

If you’ve already replaced your headlight bulb several times or notice that your headlights are flickering or getting dim, check the headlight connector, the battery terminals and the ground wire for any corrosion.

If there are any signs of corrosion, clean it off with a toothbrush, a screwdriver or some sandpaper.

Many people also apply dielectric grease inside the bulb connector as a preventative measure against potential corrosion.

6. Water in the Headlight

Water leaks or excess condensation accumulating inside the headlight assembly is another common cause of early bulb failures.

If the water reaches the headlight socket or wiring, it will create a short circuit and destroy the bulb. It also increases the chances of corrosion which can cause premature bulb failures.

Condensation normally occurs in humid and cold environments. The Subaru Crosstrek’s headlight assembly has vents to let excess heat out which also increases the chances of condensation.

If there’s only a bit of condensation, it will eventually evaporate after a few days or if you leave the headlights on for a while. Just make sure to do it with the engine running so you don’t drain the battery. You can also heat up the lens with a blow dryer to speed up the process.

Too much condensation or water droplets inside the headlight usually means the seals of the lens are broken or deteriorating. Cracks on the lens or the plastic housing can also let water in during heavy rains or while washing the car.

Here is what owners on the SubaruXVForum.com had to say:

“I just got my XV about 2 weeks ago. After making it home from the car wash I noticed moisture in the headlights on both sides.”

“After taking delivery of my 2014 XV Crosstrek Hybrid, my friend pointed out something I hadn’t noticed. Every light including both the tail lights and headlights have frost forming in them.” 

One user provided a more detailed explanation:

“The headlight assemblies are vented in the rear. Every Subaru Headlight I’ve ever removed has had some sort of means to let air in and out but also prevent water from getting in. Sometimes it’s a small rubber tube in the shape of a C or in the case of the Crosstrek, a cap that has a small tube that sticks out into it.”

“I’ve helped friends get the condensate out of headlamps by removing the bulbs in the back and heating up the lens with a hair drier or let it sit in the sun like that for the day. The opening in the vent is really too small to let the condensate out quickly although I guess it will eventually.”

If the car is still under warranty, take it back to your dealer to see if they can replace the entire headlight assembly.

You can also apply a layer of silicone around the edges of the lens to seal it back up. 

Many people also pry off the lens after heating it up for a while to break down the adhesive seal, and then reattach it using some type of glass sealant. 

7. Automatic Headlights 

Automatic headlights are a very convenient feature but they have a significant impact on the lifespan of the bulbs.

This mostly applies to halogen bulbs which are usually rated for around 500 to 1,000 hours. LED headlights generate less heat to produce the same amount of light and quality units can theoretically last 10x to 20x longer than halogens.

Automatic headlights are standard on the higher trim levels of the first and second gen Crosstrek.

You can adjust the automatic headlight sensitivity in the vehicle settings or simply turn them on manually if you’re concerned about the longevity of your headlights.

If you suspect that the automatic headlights are not working properly, check if there’s anything blocking the sensor on the dashboard. 

Related: Subaru Crosstrek Beeping? (12 Causes & Solutions)

8. Excessive Vibration

If a car experiences frequent harsh vibrations or if the headlight housing is not secure, the fragile filament in the headlight bulbs are more likely to fail.

Vibrations can also knock the headlight connectors loose which causes intermittent sparks and voltage spikes. But this should only occur if the plastic locking clips are broken or worn out.

Excessive vibration may result from various factors, including:

  • Regular off-road driving
  • Potholes and rough roads
  • Headlight assembly not bolted down tightly
  • Headlight bulbs not locked in place
  • Worn out engine mounts or suspension

If the headlight assembly has any play in it, check if any of the bolts are loose or if the brackets need to be replaced.

The headlight bulbs also need to be turned clockwise to lock them in place. They might not have been locked in all the way during installation which will cause it to rattle around in the housing.

Worn out engine mounts and suspension components can also result in excessive vibration. Although it may not be too bothersome for many owners, especially in older cars, the constant vibration can have a significant effect on the bulb’s lifespan.

Engine mounts and shock absorbers might cost a few hundred dollars to replace, but they’ll significantly improve the car’s ride quality and can potentially put your headlight issues to rest.

9. 12-Volt Battery Issues

If your 12-volt battery can no longer hold a charge, it’s not going to be able to provide enough voltage to the headlights which will lower their lifespan.

At lower voltages, the bulb won’t be able to reach proper operating temperatures and the halogen process will basically stop working, which degrades the tungsten filament quicker. 

Normally, once the tungsten evaporates, it eventually gets deposited back onto the filament. At lower temperatures, it just accumulates on the glass bulb which turns in brown and makes the headlight look dimmer.

According to Osram, a five percent deviation in the operating voltage can affect lamp life by up to 50 percent.

Most car batteries last around 3 to 4 years. If you haven’t had a new battery fitted in a couple of years and you’re frequently replacing the bulbs, it might be time for a replacement.

Before replacing the battery, you can test it with a multimeter or take it to AutoZone where they can do a proper load test.

How to Test the Battery

  • Turn the headlights on for 2 minutes to remove the surface charge
  • Set your multimeter dial to the ’20 Volts’ setting.
  • Turn off the car
  • Connect the red probe to the positive battery terminal; black probe goes to the negative

If you see less than 12 volts on the meter, you might need to replace it as it can no longer hold a charge.

Corrosion on the battery terminals can also prevent the battery from providing enough power to the car’s electrical system.  

If you see any white deposits on the battery, disconnect the battery terminals and clean them out using a toothbrush dipped in a baking soda and water mixture. Make sure the bolts are tight when you reconnect the terminals.

10. Alternator Problems

If your alternator or its voltage regulator has issues, the headlights might be getting too much or too little voltage, which will cause them to burn up faster.

The alternator provides all the electricity the car needs when the engine is running. It normally produces between 13.5 to 14.9 volts. If it stays at 15 volts or higher, you’re going to blow up the headlight bulbs quickly.

You can test the alternator’s voltage output using a multimeter. The process is similar to the steps outlined previously for a 12-volt battery test. You just need to turn on the engine to get a proper reading.

When testing the alternator, turn on the lights, AC and other electrical systems to see if it’s able to keep up with the extra load. Try revving the engine to see if it goes past 15 volts, which would mean it’s overloading the electrical system and the headlight bulbs.

You can also insert the multimeter probes into the headlight sockets to check if it’s getting the right voltage with the engine running. If not, there might be something else wrong with the wiring and you might need to check the socket or the wiring harness for possible issues.

For these types of issues, it’s best to take your car to a mechanic or an auto electrician for a proper diagnosis. Parts stores can also check if your alternator is working properly if you’re trying to minimize costs.

11. Faulty Body Integrated Unit

Subaru Crosstreks use a Body Integrated Unit or BIU which controls all of the car’s electrical system such as the lights, windows and keyless entry system.

The BIU is basically the ‘brain’ of the electrical system and is a fairly complicated circuit board/ computer module. In other vehicles, it’s called a Body Control Module.

The BIU is quite sensitive to electrical issues and can be easily damaged by short circuits or aftermarket electronics like light or sound system upgrades. 

The chips and solder joints inside the BIU can also wear out over time and cause all sorts of strange or intermittent electrical issues such as flickering headlights and blown fuses.

If you’ve already crossed out all the other possible causes in this list and you still can’t figure out why your headlights keep burning out, have a mechanic check the BIU for possible issues.

You might also solve your BIU problems by removing any aftermarket electrical or wiring modifications that have been done to the vehicle. 

Resources

https://www.subaru.com/owners/vehicle-resources.html

https://www.subaru.com/support/customer-support.html

https://www.subaru.com/recalls.html

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  • Ian Sawyer

    Growing up with a father who was a mechanic I had an appreciation for cars and motorcycles from an early age. I shared my first bike with my brother that had little more than a 40cc engine but it opened up a world of excitement for me, I was hooked. As I grew older I progressed onto bigger bikes and...

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