BMW M5 Dome Light Bulb Size

Additional Notes

• The BMW M5 dome light specifications reference two distinct bulb types across the listed model years: the 12961 and the 6411. Both operate at 12 volts and 5 watts, making them identical in electrical load despite their physical differences.
• The 12961 is a Philips part number designating a miniature wedge bulb in the T10 form factor. It uses a W2.1x9.5d base, which is a wedge-style base that seats directly into a socket without a separate holder or pins.
• The 6411 follows the ANSI standard used in the United States and Canada. It is a festoon bulb with a 36mm length and an SV8.5 base, which is a cylindrical bulb held in place by spring-loaded end caps rather than a socket.
• Because the 12961 uses a wedge base and the 6411 uses a festoon mounting system, the two bulb types are physically incompatible with each other. A socket designed for one will not accept the other.
• The BMW M5 (2008-2016) takes the 12961 bulb for the dome light position across all listed model years in that range.
• The 6411 festoon bulb is specified for the 2000-2007 model years, as well as the 1988 model year, covering the earlier generations of the M5 in these specifications.
• The T10 designation of the 12961 refers to the bulb's tubular form factor, with the number indicating a width of 10 eighths of an inch. This is a widely used size in automotive interior lighting applications.
• The SV8.5 base of the 6411 is a single-contact festoon base with an 8.5mm cap width. The "S" in the designation indicates a single contact at each end of the bulb.