Cadillac SRX Back Up Light Bulb Size

The Cadillac SRX back up light utilizes bulb sizes 12184, 2458, and 3157 depending on the specific production version. Available data covers the range from 2004 through 2016.

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
2010-2016	12184
2004-2009	3157

Bulb Specifications

Description	Bulb Size
Philips part number. Halogen bulb, specialty application. 12V.	12184
ANSI standard (US & Canada). Dual-filament wedge bulb (T25). 12V, 27W/7W.	3157

Other Locations

Additional Notes

The Cadillac SRX backup light specifications cover model years 2004 through 2016 and reference two distinct bulb types across that span.
The 3157 is an ANSI-standardized bulb used in the United States and Canada. It is a dual-filament wedge bulb in the T25 form factor, rated at 12V with a 27W/7W power split between its two filaments.
The 12184 is a Philips part number designating a 12V halogen bulb intended for specialty automotive applications.
The Cadillac SRX used the 3157 bulb for backup lights across the 2004-2009 model years.
Starting with the 2010 model year, the SRX transitioned to the 12184 bulb, which remained the specified size through 2016.
The two bulb types are not interchangeable. The 3157 is a dual-filament wedge bulb, while the 12184 is a halogen specialty bulb, and the two differ in both construction and application design.
The dual-filament nature of the 3157 means it carries two separate circuits within a single housing, a characteristic absent from the single-purpose 12184 halogen bulb.
Because the 12184 is identified by a manufacturer part number rather than an ANSI standard code, sourcing it may require cross-referencing Philips catalog data or equivalent aftermarket designations.