Chevrolet K5 Blazer Headlight Bulb Size

Additional Notes

• The Chevrolet K5 Blazer headlight specifications across 1975-1986 reference sealed beam units exclusively. All bulb types listed, including the H6054, H6024, H4651, H4652, and H4656, are ANSI-standard sealed beam assemblies rated at 12V. In each case, the entire unit is replaced rather than an internal bulb.
• The H6054 is a 5x7-inch rectangular sealed beam unit and serves as both the high beam and low beam source on two-headlamp configurations of the Chevrolet K5 Blazer from 1979 and 1982-1986. A single unit type handling both functions is characteristic of a dual-filament sealed beam design.
• The H6024 is a 7-inch round sealed beam unit and appears across the 1975-1980 model years, as well as on 1979 configurations equipped with two round headlamps. It is the only round-format sealed beam type referenced in these specifications.
• Four-headlamp configurations on the K5 Blazer use separate sealed beam units for high and low beam functions. The high beam position uses the H4651 across 1981-1986, while the low beam position uses either the H4652 (1981-1984) or the H4656 (1985-1986). All three are 4x6-inch rectangular sealed beam units.
• The H4652 is described as a variant of the H4651. Although both share the same 4x6-inch rectangular sealed beam format, they are not interchangeable between beam positions, as the H4651 is designated for high beam use and the H4652 for low beam use.
• The 1979 model year is the only year in these specifications where both round and rectangular headlamp configurations are listed simultaneously, with the H6024 assigned to two-round-headlamp fitments and the H6054 assigned to two-rectangular-headlamp fitments.
• The transition from round to rectangular headlamp formats on the K5 Blazer is reflected in the specifications by the shift from H6024 units to H6054 and H465x-series units. The H6024 does not appear in any configuration after 1980.