Pontiac Bonneville Dome Light Bulb Size

Additional Notes

• The Pontiac Bonneville dome light specifications span model years 1957 through 2003, with five distinct bulb types appearing across that range: the 906, 168, 211-2, 562, 561, and 1004, plus the 90 in 1958.
• The 561 is the most frequently specified bulb in the Pontiac Bonneville dome light data, covering model years 1975 through 1984 and again from 1986 through 1990. It is a 44mm festoon bulb with end-cap contacts, rated at 12V and 12W.
• The 562 shares the same 44mm festoon form factor and 12V, 12W rating as the 561, and the two types are specified in alternating years during the late 1980s and early 1990s, which indicates they are not universally interchangeable despite their near-identical physical and electrical characteristics.
• The 211-2 is a festoon bulb with an SV8.5 base rather than end-cap contacts, rated at 12V and 12W. Its SV8.5 base distinguishes it physically from the 561 and 562, meaning the three bulbs are not interchangeable even though their wattage ratings are identical.
• The 906 is a T10 miniature wedge bulb rated at 12V and 8W. It is specified for the Pontiac Bonneville across model years 1997-2003, with the exception of 1999, and draws notably less power than the festoon types used in earlier model years.
• The 168 is also a T10 miniature wedge bulb but is rated at 4.9W, making it the lowest-wattage bulb in the entire specification set. It appears only in the 1999 model year, and while it shares the T10 wedge form factor with the 906, its lower wattage output means the two are not equivalent replacements.
• The 1004 is a dual-filament bulb with a BAY15d bayonet base, rated at 12V with a 21/5W output. Its use as a dome light bulb is atypical, as dual-filament bayonet bulbs are more commonly associated with stop and tail light functions. It appears in the 1957, 1959, 1960, 1963, and 1964 model years.
• The 90 bulb, specified only for the 1958 Pontiac Bonneville, uses a BA15s single-contact bayonet base and is rated at 12V and 13W. The BA15s base is a single-contact variant, distinguishing it from the dual-contact BAY15d base of the 1004, and the two are not interchangeable.
• The 211-2 festoon bulb appears across two non-consecutive periods in the specifications: model years 1965-1974 and again in 1992. Its SV8.5 base requires a socket designed specifically for that contact type, which differs from the end-cap socket used by the 561 and 562.
• Across the full specification range, the dome light socket type changes at least four times, moving between bayonet bases, SV8.5 festoon bases, end-cap festoon contacts, and T10 wedge sockets. This means bulb substitutions across different era groupings of the Pontiac Bonneville are generally not feasible without socket modification.