BMW 318i Map Light Bulb Size

The BMW 318i map light requires bulb size 6411 or DE3423 depending on the specific version of the lighting component. Data for the bulb sizes covers the range from 1995 to 1998.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
1997-1998	DE3423 (Rear)
1995-1996	6411

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Festoon bulb, 41mm length, end-cap contacts. 12V.	DE3423
ANSI standard (US & Canada). Festoon bulb, 36mm length, SV8.5 base. 12V, 5W.	6411

Other Locations

Additional Notes

The BMW 318i map light specifications reference two festoon bulb types across the 1995-1998 model years: the DE3423 and the 6411.
A festoon bulb is a cylindrical lamp that seats horizontally between two spring-loaded end contacts within a recessed housing, a common configuration in interior map and dome light applications.
The DE3423 is an ANSI-standard festoon bulb with a 41mm length and end-cap contacts, operating at 12 volts.
The 6411 is an ANSI-standard festoon bulb with a 36mm length and an SV8.5 base, rated at 12 volts and 5 watts.
The SV8.5 base designation on the 6411 refers to a festoon base with an 8.5mm contact cap width, which determines socket compatibility.
The DE3423 and 6411 differ in both length and base type, making them non-interchangeable despite both being festoon-style bulbs.
The BMW 318i (1996-1995) uses the 6411 bulb for the map light position covered by these specifications.
The BMW 318i (1997-1998) uses the DE3423 bulb, with the specifications noting a Rear positional designation for that fitment.
Both bulb types conform to ANSI standards applicable in the United States and Canada, indicating standardized electrical and physical tolerances within those markets.
The positional label "Rear" associated with the DE3423 fitment indicates the bulb serves a map light located in the rear section of the cabin for the 1997-1998 model years.