Ford Thunderbird Headlight Bulb Size

Additional Notes

• The 9007 bulb is the most widely used halogen type across the Ford Thunderbird headlight specifications, appearing in both high beam and low beam positions for the 1994-1997 and 2002-2005 model years. It is a dual-filament halogen unit rated at 12V with a 65W high beam filament and a 55W low beam filament, fitted with a PX29t base, which allows a single bulb to serve both beam functions within one housing.
• The 1989-1993 Thunderbird uses separate single-filament bulbs for each beam function: the 9005 (65W, P20d base) handles the high beam, while the 9006 (55W, P22d base) handles the low beam. Although these two bulbs share a similar physical profile, they are not interchangeable, as their base configurations and wattage ratings differ.
• The 9004 bulb, used in both beam positions for the 1987-1988 model years, is a dual-filament halogen unit rated at 65W/45W with a P29t base. Its wattage output is lower than the 9007, and its base type differs, making the two bulbs physically incompatible despite both being dual-filament designs.
• Sealed beam units dominate the headlight specifications for model years 1955 through 1986. These are self-contained glass assemblies in which the lens, reflector, and filament form a single unit. When a sealed beam fails, the entire assembly requires replacement rather than just an internal bulb.
• The H5001, a 4-inch square sealed beam unit, is the most frequently specified sealed beam type in the Ford Thunderbird lineup, covering the high beam position across the 1958-1976 model years. Its low beam counterpart across the same period is the H5006, a 5.75-inch round sealed beam unit, indicating that the two positions used physically distinct assemblies during those years.
• The 1983 Thunderbird low beam specification differs from the 1984-1985 years: the 1983 model uses the H4652, a variant of the H4651, while 1984-1985 use the H4656. All three are 4x6-inch rectangular sealed beam units, but they carry distinct ANSI designations and are not confirmed as interchangeable within these specifications.
• The H6054 and H6006 are both specified as 5x7-inch rectangular sealed beam units operating at 12V, yet they carry different ANSI designations. The H6006 appears only in the 1955 model year for both beam positions, while the H6054 is specified for 1980-1982. The differing designations indicate they are distinct part numbers and are not treated as substitutes for one another.
• The H6024, a 7-inch round sealed beam unit, appears across three separate periods in the Thunderbird specifications: the 1956-1957 model years and again for 1977-1979, covering both high and low beam positions in each case. As a sealed beam assembly, it is subject to the same full-unit replacement requirement as all other sealed beam types listed.