Subaru Legacy Headlight Bulb Size

Additional Notes

• The 9005 bulb is the most consistently specified high beam type across the Subaru Legacy, covering the 2008-2019 model years. It is a single-filament halogen bulb rated at 65 watts, designed exclusively for high beam use, and is not interchangeable with dual-filament bulb types.
• The H11 bulb serves as the low beam type for the Subaru Legacy from 2015-2019 in halogen capsule headlamp configurations. It is a single-filament halogen bulb commonly rated at 55 watts and uses a proprietary L-shaped connector, making it incompatible with earlier H-series connectors despite similar wattage ratings.
• The H7 bulb is specified for low beam use across the 2008-2014 Legacy. Like the H11, it is a single-filament halogen bulb, but it uses a two-pin connector that is physically distinct from the H11 fitting, meaning the two types are not interchangeable even though both serve the low beam function.
• The D4S bulb is specified for low beam use on 2015-2018 Legacy models equipped with HID headlamps. It is a high-intensity discharge bulb that operates without a filament, instead producing light through an electrical arc. The D4S type is self-ballasted and does not require a separate igniter, distinguishing it from the D2S type.
• The 9003 bulb, also known as HB2 or H4, is a dual-filament halogen type specified for both high and low beam functions on the 1992-1997 Legacy. Because both beams share a single bulb, replacing one beam requires replacing the entire unit, unlike systems that use separate bulbs for each function.
• The 9007 bulb, specified for both high and low beam on the 1998-1999 Legacy, is also a dual-filament halogen type. Although it shares this dual-filament characteristic with the 9003, the two are not interchangeable due to differences in their base configurations and filament positions.
• The 9004 bulb is specified for both high and low beam on the 1990-1991 Legacy. It is a dual-filament halogen type, but its asymmetric base design means it can only be installed in one orientation, and it is not compatible with 9007 or 9003 sockets despite serving the same dual-beam purpose.
• For the 2019 Legacy high beam, the specification includes the qualifier "With Halogen Capsule Headlamps," indicating that the 9005 fitment applies only to that headlamp variant. This distinction is relevant because vehicles equipped with a different headlamp system would not use this bulb type.
• The low beam system on the 2015-2018 Legacy presents a dual-fitment situation, where H11 and D4S are each valid depending on whether the vehicle has halogen capsule or HID headlamps. These two bulb types operate on fundamentally different technologies and are entirely incompatible with each other's housings and electrical systems.
• Across the full range of Legacy specifications provided, four distinct high beam bulb types appear: 9004, 9003, 9007, and 9005. Each uses a different base and connector, and none of these types are cross-compatible with one another, making correct year and trim identification necessary before replacement.