Chevrolet El Camino Dome Light Bulb Size

Additional Notes

• The Chevrolet El Camino dome light bulb specification covers model years 1959 through 1987, with three distinct bulb types used across that span: the 1004, the 211-2, and the 561.
• The 561 and 211-2 are both festoon-type bulbs, meaning they are cylindrical in form and mount by pressing between two spring clips or contacts within the fixture housing rather than using a twist or push-in socket.
• The 561 bulb is rated at 12V and 12W and measures 44mm in length, with end-cap contacts at each end. It follows the ANSI standard applicable in both the United States and Canada.
• The 211-2 bulb shares the same 12V and 12W electrical rating as the 561 but measures 41mm in length and uses an SV8.5 base. Despite the identical wattage, the 3mm difference in length and the differing base type make the two festoon bulbs non-interchangeable without a compatible fixture.
• The Chevrolet El Camino (1974-1987) uses the 561 bulb for the dome light, representing the longest continuous fitment of a single bulb type across the model's history in these specifications.
• Model years 1964-1973 use the 211-2 bulb, which preceded the transition to the 561 beginning with the 1974 model year.
• The 1004 bulb, used in the 1959-1960 El Camino, is a dual-filament bulb with a BAY15d bayonet base, rated at 12V with a 21/5W output. The dual-filament design provides two separate brightness levels within a single bulb.
• The 1004 is noted as a variant of the 1157 bulb and shares its BAY15d bayonet base, which uses two offset pins to ensure correct orientation during installation.
• The shift from the 1004 bayonet-base bulb in 1959-1960 to the 211-2 festoon-type bulb from 1964 onward reflects a change in fixture design, as the two base types are physically incompatible with each other.
• All three bulb types in these specifications conform to ANSI standards recognized in both the United States and Canada, indicating standardized electrical and physical tolerances across each type.