Chevrolet Monte Carlo Dome Light Bulb Size

Additional Notes

• The Chevrolet Monte Carlo dome light specifications span model years 1970 through 2007, with three distinct festoon bulb types and one bayonet-base bulb type appearing across that range.
• The 578 bulb is the most frequently specified type in the later production years, covering the 2000-2007 Monte Carlo. It is a festoon bulb measuring 41mm in length with end-cap contacts, rated at 12V and 12W under the ANSI standard.
• The 561 bulb is the most widely used type across the full specification range, appearing in the 1974-1975, 1979-1986, 1988, and 1995-1996 model years. Like the 578, it is a 12V, 12W festoon bulb, but it measures 44mm in length with end-cap contacts.
• The 562 bulb, specified for the 1997-1999 model years, shares the same 44mm festoon form and 12V, 12W rating as the 561. The 561 and 562 are physically similar but are distinct ANSI part numbers and are not listed as interchangeable within these specifications.
• The 211-2 bulb appears in the 1970-1973 and 1976-1977 model years. It is a 41mm festoon bulb rated at 12V and 12W, but it uses an SV8.5 base rather than end-cap contacts, which distinguishes it from the 578 despite sharing the same length.
• Because the 578 and 211-2 bulbs share a 41mm length but use different base types, end-cap versus SV8.5, they are not physically interchangeable, and substituting one for the other would require a compatible socket.
• The 1004 bulb is specified for the 1978 and 1982 Monte Carlo. It is a dual-filament bulb with a BAY15d bayonet base, rated at 12V with a 21/5W output, and is described as a variant of the 1157. Its electrical and mechanical design differs substantially from the festoon types used in all other listed years.
• The 1004 bayonet-base bulb is not interchangeable with any of the festoon types in these specifications, as the BAY15d base requires a dedicated socket that does not accept festoon-style bulbs.
• All bulb types listed across the full specification range conform to ANSI standards applicable in the United States and Canada.
• The 12W rating shared by the 578, 562, 561, and 211-2 bulbs indicates a consistent power draw for the dome light function across most of the Monte Carlo's production history, with the 1004's dual-filament 21/5W rating representing a notable departure in the years it was specified.