2021 Subaru Crosstrek Bulb Sizes

Quick reference

*Integrated LED assembly, not a replaceable bulb.

The 2021 Subaru Crosstrek, a popular compact SUV known for its adventurous spirit and standard all-wheel drive, comes with various lighting configurations depending on the trim level. Understanding the specific bulb sizes for your Crosstrek is crucial whether you're replacing a burnt-out bulb or considering an upgrade to LED lighting.

For the 2021 model year, Subaru offered a mix of halogen and LED lighting from the factory. Base, Premium, and Sport trims typically came equipped with halogen low and high beams, while the Limited trim featured full LED headlights with integrated LED daytime running lights (DRLs). Fog lights across all trims are generally halogen.

LED vs Halogen Upgrade Considerations

Upgrading from halogen to LED bulbs in your 2021 Subaru Crosstrek can significantly improve light output, modernize the look of your vehicle, and potentially increase bulb lifespan. However, there are several key points to consider:

• CANBUS Errors: Modern vehicles like the Crosstrek use a CANBUS (Controller Area Network Bus) system to monitor electrical components. LED bulbs draw significantly less power than halogen bulbs, which can sometimes trigger "bulb out" warnings or hyper-flashing (for turn signals) as the CANBUS system interprets the lower power draw as a burnt-out bulb. To counteract this, many aftermarket LED bulbs come with built-in CANBUS decoders, or you may need to purchase separate load resistors or decoders.
• Adapter Needed: For some applications, particularly headlights, you might need specific adapters to properly seat the aftermarket LED bulb into the housing and ensure proper beam pattern. Always check the fitment guides provided by the LED bulb manufacturer.
• Beam Pattern: Not all LED bulbs are created equal. Poorly designed LED bulbs can create a scattered light pattern or glare, which is not only ineffective for you but can also be blinding to oncoming drivers. Look for LED bulbs designed to mimic the filament placement of their halogen counterparts to ensure a proper beam pattern in your Crosstrek's headlight housing. For projector-style halogen headlights (like those found on some Crosstreks), reputable LED conversions usually work well. For reflector housings, careful selection and aiming are critical.
• DRL Functionality: If you have halogen high beams that also function as DRLs, switching to LED high beams might affect the DRL brightness. Some LED bulbs have a dual-intensity feature to mimic this, while others may only operate at full brightness.

How to Replace Each Bulb

Replacing bulbs on your 2021 Crosstrek is generally a straightforward DIY task for most external and internal lights. Always consult your owner's manual for specific instructions and warnings.

• Headlights (Low/High Beam): Access is usually from behind the headlight assembly in the engine bay. You may need to remove a plastic cover or air intake duct for better access. Twist the bulb counter-clockwise to remove, unplug the electrical connector, and reverse the process for installation. For LED headlights, these are integrated units and usually require professional service if they malfunction.
• Fog Lights: Access is often from underneath the vehicle or by removing a splash guard in the wheel well. Philips head screws or plastic clips typically secure the housing or cover.
• Turn Signals (Front & Rear): For the front, access is similar to the headlights. For the rear, open the trunk/hatch and locate the access panel behind the tail light assembly. Twist the bulb socket, pull out the old bulb, and push in the new one.
• Brake/Tail Lights: Similar to the rear turn signals, access is typically through an access panel in the trunk/hatch.
• Reverse Lights: Also accessed from an access panel in the trunk/hatch.
• License Plate Lights: Usually accessed by removing a few small screws holding the light housing in place on the tailgate.
• Side Markers: Often located on the side mirror or fender, these usually pop out with a gentle pry tool.
• Dome/Map Lights: Carefully pry off the lens cover with a plastic trim tool or small flathead screwdriver. The bulbs are usually pushed or twisted into place.

Common Lighting Issues for this Generation

While the 2021 Crosstrek is a reliable vehicle, some common lighting-related observations or issues for this generation (which spans 2018-2023 for the second generation) can include:

• Halogen Headlight Dimness: Owners of halogen-equipped models sometimes report the headlights being somewhat dim compared to vehicles with LED lighting, leading many to consider upgrades.
• Condensation in Headlight Assemblies: Occasionally, owners have reported minor condensation inside the headlight or taillight housings. This is often normal due due to temperature fluctuations, but excessive moisture can indicate a seal issue.
• Bulb Life: Incandescent bulbs, particularly those exposed to frequent vibrations (like turn signals or brake lights), will eventually burn out. Keeping spare bulbs on hand is always a good idea.

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