Lexus IS250 Dome Light Bulb Size

The Lexus IS250 dome light requires bulb size DE3021 or 13050 depending on the specific version required for the interior overhead illumination. Data for the specified lighting components covers the range from 2006 through 2009.

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
2007-2009	DE3021
2006	13050

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Festoon bulb, 31mm length, end-cap contacts. 12V.	DE3021
OEM/Wagner part number. Halogen bulb, specialty application. 12V.	13050

Other Locations

Additional Notes

The Lexus IS250 dome light uses two distinct bulb types across its model years: the DE3021 for 2007-2009 and the 13050 for 2006.
The DE3021 is an ANSI-standardized festoon bulb, meaning it follows a defined North American specification recognized across the US and Canada.
Festoon bulbs are cylindrical in form and make electrical contact through metal caps at each end rather than through a base socket, which is characteristic of the DE3021's end-cap contact design.
The DE3021 has a 31mm length, which is a critical fitment factor, as festoon bulbs are sized by their length and an incorrect length will not seat properly in the housing.
Both the DE3021 and the 13050 operate at 12 volts, consistent with standard automotive electrical systems.
The 13050 is designated as an OEM/Wagner part number rather than an ANSI code, indicating it is a manufacturer-specific reference rather than a universal industry classification.
The 13050 is a halogen bulb intended for a specialty application, which distinguishes it technically from the non-halogen DE3021 festoon type used in later model years.
The 2006 Lexus IS250 uses the 13050, and substituting a DE3021 in its place would not be a direct interchange due to the differing bulb technologies and part classifications.
The shift from the 13050 in 2006 to the DE3021 in 2007 represents a change in bulb type between those model years, meaning parts are not interchangeable across that boundary.
When sourcing a replacement DE3021, the ANSI standardization means equivalent bulbs from multiple manufacturers are generally compatible, provided the 31mm length and end-cap contact design are matched.