How to Choose, Maintain, and Upgrade Your Subaru WRX Headlights: A Complete Guide for Owners

If you drive a Subaru WRX, you already know it’s more than just a car—it’s a tool for adventure, a daily commuter, and a reflection of your passion for performance. But even the most reliable machines need care, and few components are as critical to both safety and performance as your headlights. Whether you’re dealing with dimming bulbs, yellowed lenses, or simply want to upgrade for better visibility, understanding how to maintain, repair, and enhance your WRX’s headlights will keep you safer on the road and preserve your vehicle’s value. This guide dives deep into everything you need to know, from basic maintenance to advanced upgrades, so you can make informed decisions that balance functionality, cost, and compliance.

Why WRX Headlights Matter More Than You Think

The Subaru WRX’s headlights aren’t just about aesthetics—they’re engineered to meet strict safety standards while complementing the car’s all-wheel-drive performance and turbocharged power. Original Equipment Manufacturer (OEM) headlights on newer WRX models (2015–present) typically use High-Intensity Discharge (HID) technology with halogen backups, while older models (pre-2015) often rely on halogen bulbs. Both systems are designed to project light far down the road, cut through rain, fog, and snow, and provide adequate peripheral vision. However, like any automotive component, headlights degrade over time due to UV exposure, road debris, and normal wear. Dimming, yellowing, or misaligned beams don’t just reduce visibility—they increase your risk of accidents, especially during dawn, dusk, or inclement weather. Understanding how your headlights work and how to care for them is the first step toward keeping your WRX safe and reliable.

Common WRX Headlight Problems (and How to Fix Them)

Even with proper care, WRX headlights will eventually show signs of wear. Here are the most frequent issues owners face, along with practical solutions:

1. Dimming or Flickering Bulbs

Bulbs dim over time as their filament weakens (halogen) or gas mixture depletes (HID). Flickering often indicates a loose connection, a failing ballast (in HID systems), or a corroded socket.

• Fix it: Start by checking the bulb connections. Use a wire brush to clean corroded terminals and tighten any loose screws. If the bulb still flickers, replace it—don’t wait for it to burn out completely. For HID systems, a faulty ballast (located near the headlight assembly) may need professional replacement, as it’s integrated into the housing.

2. Yellowed or Cloudy Lenses

UV rays, road salt, and debris cause the polycarbonate lens to oxidize, creating a yellowish film that blocks light output. This is especially common in areas with harsh winters or high pollution.

• Fix it: For mild discoloration, use a headlight restoration kit (available at auto parts stores). These kits typically include sandpaper (1000–3000 grit), polish, and a protectant. Follow the instructions carefully: wet-sand the lens to remove oxidation, polish to restore clarity, and apply a UV-resistant sealant to prevent future yellowing. Severe cases may require professional resurfacing or lens replacement.

3. Misaligned Beam Patterns

Over time, vibrations from driving on rough roads or impacts (e.g., potholes) can knock the headlight assembly out of alignment, causing the beam to point too high, low, or to one side. Misaligned lights blind oncoming drivers and reduce your own visibility.

• Fix it: Most WRX models have adjustable headlight assemblies with horizontal and vertical screws. Park your car on a flat surface 25 feet from a wall, turn on the low beams, and adjust the screws until the beam pattern aligns with manufacturer specifications (found in your owner’s manual). If you’re unsure, a certified mechanic or auto electrician can do this quickly with a beam alignment tool.

4. Water Inside the Headlight Housing

Older WRX models (pre-2015) with halogen headlights are prone to water intrusion due to cracked seals or worn gaskets. Water can corrode internal components, cause fogging, and reduce light efficiency.

• Fix it: Inspect the housing for cracks or gaps. If the seal is damaged, replace the gasket (inexpensive and available online) and apply silicone sealant around the edges. For severe water damage, remove the housing, dry it thoroughly with a heat gun or compressed air, and replace any corroded bulbs or wiring.

Maintaining Your WRX Headlights: A Proactive Approach

Preventing problems is cheaper and easier than fixing them. Here’s a year-round maintenance routine to keep your headlights in top condition:

1. Regular Cleaning

Road grime, bug splatter, and tar can accumulate on lenses, reducing light output by up to 50%. Clean your headlights weekly with a mild detergent (avoid harsh chemicals that damage polycarbonate) and a microfiber cloth. For stuck-on debris, use a dedicated automotive lens cleaner or a 50/50 mix of white vinegar and water (vinegar cuts through grease without harming the plastic).

2. UV Protection

Polycarbonate lenses degrade when exposed to prolonged sunlight. After cleaning, apply a UV-resistant headlight protectant (e.g., 3M Headlight Lens Restorer Coating). These products create an invisible barrier that blocks UV rays and slows oxidation. Reapply every 3–6 months for best results.

3. Check Seals and Gaskets

Inspect the headlight housing seals annually for cracks, tears, or brittleness. Replace them immediately if you notice damage—even small gaps can let in moisture or debris. Most OEM seals cost under $20 and can be installed with basic tools (a screwdriver and trim removal tool).

4. Test Bulb Life

Halogen bulbs last 400–600 hours; HID bulbs last 2,000–3,000 hours. If you drive 15,000 miles annually (average for WRX owners), plan to replace halogen bulbs every 2–3 years and HID bulbs every 5–7 years. Keep spare bulbs in your glove box—you never know when a failure might happen.

Upgrading Your WRX Headlights: Balancing Performance, Cost, and Legality

If your OEM headlights no longer meet your needs—whether you want brighter light, better beam patterns, or a modern LED look—upgrading is an option. But not all upgrades are created equal. Here’s what to consider:

1. OEM vs. Aftermarket Replacement

• OEM Replacement: The safest choice for maintaining warranty coverage and compliance with safety standards. Companies like Denso (a Subaru supplier) make exact replicas of WRX headlights. They’re pricier ($300–$600 per assembly) but guaranteed to fit and perform like the original.
• Aftermarket Replacement: More affordable ($150–$400 per assembly) and often include upgrades like LED bulbs or improved reflectors. Brands like Morimoto, DEPO, and DEPO offer WRX-specific housings designed to fit without modifications. Always check for DOT (Department of Transportation) or ECE (European Economic Community) certification—these labels ensure the lights meet legal brightness and beam pattern requirements.

2. Bulb Upgrades: Halogen, HID, or LED?

• Halogen: The OEM standard for older WRXs. Inexpensive ($10–$30 per bulb) and easy to replace, but limited in brightness and color temperature (typically 3,200K–4,300K, which casts a yellowish light).
• HID (Xenon): Found in newer WRXs (2015+). Brighter (up to 3x more light than halogen) and whiter (4,300K–6,000K), with better visibility in low light. However, HID bulbs are fragile, expensive ($100–$300 per bulb), and require a ballast for operation. Retrofitting HID bulbs into halogen housings is possible but often illegal (due to improper beam patterns) and voids warranties.
• LED: The latest trend in aftermarket upgrades. LEDs are energy-efficient, last 25,000–50,000 hours, and produce a crisp white light (5,000K–6,500K). Look for LED bulbs with a “canbus” design to avoid error codes on your dashboard. Top brands like Philips Ultinon and Sylvania Smart LED offer WRX-compatible options. Note: Some LED bulbs may require additional cooling fans to prevent overheating—cheap models often skip this, leading to premature failure.

3. Legal Considerations

In the U.S., headlights must emit a white or amber light (no blue tints) and project a minimum of 200 feet forward. Brightness is regulated: low beams must not exceed 225,000 candelas, and high beams must not exceed 750,000 candelas. Aftermarket upgrades that exceed these limits or project light sideways (blinding other drivers) are illegal. Always check your state’s specific laws—some states (e.g., California) have stricter rules. When in doubt, stick to DOT/ECE-certified parts.

Troubleshooting WRX Headlight Issues: A Step-by-Step Guide

Even with maintenance and upgrades, headlight problems can still occur. Use this checklist to diagnose common issues:

Problem: Headlights won’t turn on

• Check the fuse: Locate the headlight fuse in your WRX’s fuse box (consult the owner’s manual for the exact location). Use a multimeter to test continuity—if there’s no current, replace the fuse.
• Inspect the relay: The headlight relay sends power from the fuse box to the bulbs. Swap it with a similar-rated relay (e.g., from another circuit like the horn) to test if it’s faulty.
• Test the bulbs: Remove the bulb and check for broken filaments (halogen) or corrosion (HID/LED). Use a battery and a wire to jump the bulb—if it lights up, the issue is with the car’s electrical system, not the bulb.

Problem: One headlight is dimmer than the other

• Clean both lenses: Uneven dirt or oxidation can make one light appear dimmer.
• Check bulb wattage: Ensure both bulbs are the same type and wattage (e.g., 55W halogen, 35W HID). Mismatched bulbs cause uneven output.
• Inspect the ground wire: A corroded or loose ground wire can reduce power to one headlight. Trace the ground wire from the housing to the chassis and clean/tighten connections.

Problem: Headlights flicker at high speeds

• Loose wiring: Vibrations from driving can loosen connections in the headlight circuit. Tighten all screws and connectors in the housing and engine bay.
• Faulty alternator: A failing alternator may not supply consistent voltage, causing flickering. Use a voltmeter to test battery voltage—at 2,000 RPM, it should read 13.8–14.8V. Lower voltage indicates a failing alternator.

Final Thoughts: Invest in Visibility, Invest in Safety

Your Subaru WRX’s headlights are a critical safety feature, not an afterthought. By understanding how to maintain them, troubleshoot common issues, and upgrade wisely, you’ll keep your car performing at its best while ensuring you and your passengers stay safe on the road. Remember: cutting corners on headlight quality or installation can lead to legal trouble, reduced visibility, and costly repairs down the line. Whether you’re replacing a bulb, restoring yellowed lenses, or upgrading to LEDs, prioritize certified parts, follow manufacturer guidelines, and when in doubt, consult a professional. Your WRX deserves the best—and so do you.