INFINITI QX4 Headlight Bulb Size

Additional Notes

• The 9004 bulb, used in the INFINITI QX4 for 1997-1998, is a dual-filament halogen type operating at 12V with a high beam output of 65W and a low beam output of 45W. Its P29t base handles both beam functions within a single bulb, meaning one unit serves both the high beam and low beam headlight positions simultaneously.
• The 9003 bulb, fitted to 1999-2000 QX4 models equipped with halogen capsule headlamps, is also a dual-filament halogen type with a P43t base, rated at 12V and 60W/55W for high and low beams respectively. Like the 9004, it covers both beam functions in a single unit.
• For 1999-2000 QX4 models equipped with HID headlamps, the high beam position uses an H1 bulb rather than a dual-filament type. The H1 is a single-filament halogen bulb with a P14.5s base, rated at 12V and 55W, and follows the ECE standard, though it also carries approval for use in the United States and Japan.
• The D2R bulb serves as the low beam source in HID-equipped 1999-2000 QX4 models and as the sole low beam bulb in 2001-2003 models. It is a high-intensity discharge xenon type rated at 85V and 35W, requiring an external ignitor to initiate the arc. Its P32d-3 base and "R" designation indicate it is specifically designed for reflector-type headlamp housings.
• The 9005 bulb, used exclusively in the high beam position on 2001-2003 QX4 models, is a single-filament halogen type with a P20d base, rated at 12V and 65W. Because it handles only the high beam function, these model years pair it with a separate D2R bulb for low beam operation.
• The INFINITI QX4 (1999-2000) offered two distinct headlamp configurations: halogen capsule headlamps using the 9003 bulb for both beams, and HID headlamps pairing the H1 for high beam with the D2R for low beam. These two configurations are not interchangeable, as they involve different bulb types, base fittings, and operating voltages.
• The transition from the 9004 dual-filament bulb in 1997-1998 to separate high and low beam bulbs in later years reflects a shift in headlamp architecture. The 9004 uses a P29t base, which is physically incompatible with the P43t base of the 9003, the P14.5s base of the H1, and the P32d-3 base of the D2R, making cross-year substitution impossible without housing modifications.
• The D2R's 85V operating voltage stands in sharp contrast to the 12V rating of all halogen bulbs in these specifications. This difference means HID and halogen components operate on fundamentally different electrical systems, and the external ignitor required by the D2R is absent from halogen headlamp assemblies.