GMC K1500 Headlight Bulb Size

Additional Notes

• The GMC K1500 headlight specifications span the 1979-1999 model years, covering both high beam and low beam positions across multiple headlamp system configurations.
• The H6054 is the most frequently referenced bulb type across these specifications. It is a 5x7-inch rectangular sealed beam unit operating at 12V, conforming to ANSI standards for the US and Canada. As a sealed beam unit, the entire assembly is replaced rather than an individual bulb.
• The 9005 and 9006 are the two halogen capsule bulb types specified for the K1500. The 9005 is a 12V, 65W single-filament halogen bulb with a P20d base used for high beam, while the 9006 is a 12V, 55W single-filament halogen bulb with a P22d base used for low beam. These two types share a similar physical form but differ in wattage and base type, making them non-interchangeable.
• For the 1992-1998 model years, the GMC K1500 carried two distinct headlamp system options: sealed beam headlamps using the H6054 for both high and low beam, and halogen capsule headlamps using the 9005 for high beam and the 9006 for low beam. The correct bulb type is determined strictly by which system is installed on the vehicle.
• In the 1988-1991 model years, four-rectangular-headlamp configurations used the H4701 for high beam and the H4703 for low beam. Both are 7-inch round sealed beam units operating at 12V, replaced as complete assemblies.
• For the 1982-1986 model years, four-headlamp configurations used 4x6-inch rectangular sealed beam units. The high beam position used the H4651, while the low beam position used the H4656, with the exception of 1983, where the low beam unit is listed as the H4652, a variant of the H4651.
• The 1979-1980 model years include a two-round-headlamp configuration using the H6024, a 7-inch round sealed beam unit operating at 12V, for both high and low beam positions.
• Sealed beam units such as the H6054, H4701, H4651, H4703, H4656, H4652, and H6024 are not interchangeable with halogen capsule bulbs such as the 9005 and 9006, as the two systems represent fundamentally different headlamp assembly types.