G37 Headlights: The Complete Guide to Upgrades, Replacement, and Maintenance
The Infiniti G37, a celebrated sports coupe and sedan, is renowned for its performance and style. However, one of the most common and impactful areas owners seek to improve or maintain is the headlight system. Whether you're dealing with aged, yellowed lenses, seeking a modern lighting upgrade, or simply need to replace a faulty component, understanding your G37 headlights is crucial. This comprehensive guide provides all the necessary information, from basic bulb replacement to advanced custom modifications, ensuring you can make informed decisions to enhance your vehicle's visibility, safety, and aesthetics. The right approach to your G37's headlights can significantly transform the car's appearance and nighttime driving experience, making it a worthwhile investment for any owner.
Understanding G37 Headlight Types and Generations
The Infiniti G37 was produced from 2007 to 2015, and its headlights evolved during this period. Knowing which type you have is the first step in any maintenance or upgrade project. The primary distinction lies between the standard halogen headlights and the optional factory High-Intensity Discharge (HID) system.
Standard Halogen Headlights were common on base models, particularly in the early years. These units use a traditional halogen bulb for both the low and high beams. They are characterized by a simpler, less intricate internal reflector design. The light output is a warmer, yellower color compared to HIDs, and overall illumination is generally considered adequate but not exceptional by modern standards. The main advantage of halogen systems is lower replacement cost for the bulbs themselves.
The factory HID system, often marketed as Xenon headlights, was a popular option. These are easily identifiable by their bright, white light with a slight blue hue and a distinctively sharp cut-off line on the road. HID systems use a bulb that creates an arc of electricity within a gas-filled chamber, producing far more light than halogen bulbs. They require a separate component called a ballast to ignite and regulate the power. G37s with HIDs also feature automatic leveling and headlight washers in many markets to comply with regulations due to the increased brightness. The light output and color temperature are superior, offering much better nighttime visibility.
Furthermore, a visual difference exists between the headlights on the G37 Coupe (and its convertible counterpart, the G37 Convertible) and the G37 Sedan. The coupe headlights have a more aggressive, slanted design that flows with the car's profile, while the sedan headlights are more upright and formal. There was also a mid-cycle refresh around 2010-2011 for the Coupe (2011 model year for the Sedan), which brought slight changes to the headlight lens pattern and internal styling, though the fundamental technology (Halogen vs. HID) remained the same.
The Complete G37 Headlight Bulb Replacement Guide
Replacing bulbs in your G37 is a common task, as all bulbs have a finite lifespan. The process differs significantly between halogen and HID systems.
For G37 models with standard Halogen Headlights, the bulb replacement is a relatively straightforward DIY job. The low beam and high beam bulbs are typically separate. Access is gained from within the engine bay. It is crucial to consult your owner's manual for the specific bulb size (e.g., H11 for low beam, H9 for high beam are common). Before starting, ensure the headlight switch is off. When handling a new halogen bulb, avoid touching the glass capsule with your bare fingers. Skin oils can create hot spots on the glass when the bulb is illuminated, leading to premature failure. Use a clean cloth or gloves during installation. After replacing the bulb, always check the headlight aim to ensure it is properly aligned and not blinding other drivers.
For G37 models with the factory HID system, the process is more complex. The HID bulb itself, often a D2S or D2R type, is more fragile and expensive. The ballast, which supplies the high voltage needed to ignite the bulb, can also fail. Diagnosing a problem requires determining if the issue is the bulb, the ballast, or a fuse. A common symptom of a failing HID bulb is flickering, taking longer to reach full brightness, or changing color to a pinkish hue. Replacing an HID bulb requires careful disconnection of the wiring harness and the bulb from the headlight housing. Due to the tight space and high voltage risk, many owners prefer to have this done by a professional. If one HID bulb fails, it is often recommended to replace both bulbs as a pair to ensure consistent color and light output, as HID bulbs can shift color slightly with age.
Restoring Cloudy G37 Headlight Lenses
Over time, the polycarbonate plastic lenses on G37 headlights can become cloudy, yellowed, and hazy due to prolonged exposure to UV radiation from the sun and environmental contaminants. This degradation severely reduces light output and diminishes the car's appearance. Restoration is a cost-effective alternative to purchasing new, expensive headlight assemblies.
The cloudiness is not just on the surface; it is micro-fissures and oxidation in the plastic. Therefore, a simple clean will not solve the problem. A proper restoration involves a multi-step sanding process to remove the damaged outer layer. This typically starts with a coarse grit sandpaper (e.g., 400 grit) to eliminate the heavy oxidation, followed by progressively finer grits (600, 800, 1000, 2000, 3000) to smooth the surface and remove the scratches from the previous stage. The sanding is always done with water as a lubricant to prevent clogging the sandpaper and overheating the plastic.
After sanding, the lens will be smooth but dull. The final, critical step is applying a UV-resistant clear coat or sealant. This step is non-negotiable. Sanding removes the factory UV protective layer, and without a new one, the headlights will re-cloud much faster, often within a few months. High-quality headlight restoration kits include this sealant. Alternatively, professionals may use a UV-cured clear coat that is more durable. A properly executed restoration can make old headlights look nearly new and restore full light output, often lasting for two years or more before needing a touch-up.
Upgrading G37 Headlights for Improved Performance and Style
Many owners look beyond simple maintenance to upgrades that enhance both function and form.
HID Conversion Kits: For G37s equipped with halogen headlights, one of the most popular upgrades is installing an aftermarket HID conversion kit. These kits include HID bulbs, ballasts, and all necessary wiring. It is imperative to choose a quality kit designed for your specific vehicle. A critical part of this conversion is ensuring the HID bulbs are correctly aligned within the halogen reflector housing. Halogen and HID bulbs have different filament or arc placement, and incorrect positioning can cause poor beam pattern, glare, and scatter, blinding other drivers. Retrofit projectors are the ideal solution for this, but a well-designed kit can provide a significant improvement in light output if installed correctly.
LED Bulb Replacement: Modern LED bulbs have become a highly popular upgrade path. They offer several advantages: extremely long lifespan, lower power consumption, and a bright, white light that is close to daylight. LED technology has advanced to the point where many bulbs are designed as direct replacements for both halogen and HID sockets. For a G37 with halogen lights, LED bulbs can be a plug-and-play upgrade that provides much better visibility without the complexity of an HID kit's ballasts. For HID-equipped cars, LED replacements can offer a similar light color with instant-on capability, unlike HIDs which take a moment to warm up. When purchasing LED bulbs, look for models that have a good reputation for correct beam pattern placement to avoid creating glare.
Complete Aftermarket Assemblies: For the most dramatic style change, owners can opt for complete aftermarket headlight assemblies. These are entire new units that replace the factory headlights. They often feature blacked-out housings, LED accent strips (like halo rings or light bars), and integrated LED turn signals. Some high-end options come with built-in LED projectors for superior performance. This option is the most expensive but delivers a complete transformation. It is vital to purchase from reputable brands, as cheap aftermarket lights can suffer from poor light output, water leakage, and premature LED failure.
Custom Retrofitting: This is the ultimate headlight upgrade for the dedicated enthusiast. A custom retrofit involves opening the factory headlight housing and installing high-quality projector units from brands like OEM Audi (AL), BMW (BMW), or Morimoto. This process is labor-intensive and requires baking the headlights in an oven to soften the adhesive for opening. The result, however, is the best possible beam pattern with a sharp cut-off and maximum light output, combined with the ability to use high-performance HID or LED bulbs. This is considered the pinnacle of functional headlight modification.
Troubleshooting Common G37 Headlight Issues
Beyond bulb failure, G37 owners may encounter other common headlight problems.
Condensation Inside the Headlight: It is normal to see slight condensation inside a headlight under certain conditions, which should clear quickly. However, persistent pooling of water indicates a failed seal. The problem could be a cracked lens, a damaged housing, or a faulty seal between the lens and the housing. Small amounts of moisture can sometimes be dried out by removing the rear bulb access caps and letting the unit air out. For major leaks, the headlight must be removed, dried thoroughly, and the source of the leak identified and sealed with appropriate adhesive. In severe cases, replacement of the entire assembly may be necessary.
Automatic Leveling System Malfunction (HID models): G37s with HID headlights have an automatic leveling system that adjusts the beam height based on the vehicle's load. If this system fails, you may see error messages on the dashboard, or the headlights may point too low or too high. The system uses sensors attached to the suspension and actuators on the headlights themselves. Diagnosis requires a diagnostic scanner to read fault codes from the AFS (Adaptive Front-lighting System) module. Common failures include a broken leveling sensor arm or a faulty actuator motor inside the headlight.
Flickering Lights: Flickering can be caused by a few issues. A simple cause is a loose connection or a failing bulb. With HID systems, a flickering light that eventually goes out often points to a failing ballast that can no longer sustain the electrical arc. If both headlights are flickering, the problem could be related to the vehicle's electrical system, such as a weak battery or a failing alternator not providing stable voltage.
The Importance of Proper Headlight Aiming
After any headlight service—whether it's bulb replacement, restoration, or installation of new assemblies—the headlights must be properly aimed. Incorrectly aimed headlights are a serious safety hazard. Headlights pointed too high will blind oncoming drivers, reducing their ability to see and creating a dangerous situation. Headlights pointed too low will severely limit your own viewing distance, reducing your reaction time at night.
Professional headlight aiming uses a specialized optical aiming machine that ensures the beam pattern is precisely calibrated to manufacturer specifications. While a rough adjustment can be made against a wall in a dark garage, it is not a substitute for a professional alignment. The adjustment screws are located on the headlight housing itself, allowing for vertical and horizontal adjustment. This is a critical final step that ensures your investment in new bulbs or housings translates into safe, effective illumination.
Conclusion: Making the Right Choice for Your G37
The headlights are a vital component of your Infiniti G37, directly impacting safety, functionality, and curb appeal. From simple bulb swaps to complete custom retrofits, the range of options allows every owner to find a solution that fits their needs and budget. Regular maintenance, like cleaning and timely bulb replacement, ensures consistent performance. Addressing cloudiness through restoration can rejuvenate the car's look and restore light output. For those seeking improvement, modern LED technology offers a fantastic balance of performance and ease of installation. Ultimately, investing in your G37's headlights is an investment in safer driving and a more enjoyable ownership experience, preserving the character and capability of this modern classic for years to come.