Cadillac Escalade Back Up Light Bulb Size

The Cadillac Escalade back up light utilizes bulb sizes 921, 7440, 2458, 3157, and 3156 across various production periods. Available information covers a time range from 1999 through 2023.

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
2023	921
2007-2014	7440
2002-2006	3157
1999-2000	3156

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Wedge bulb (T15). 12V, 16W.	921
ANSI standard (US & Canada). Single-filament wedge bulb (T20). 12V, 21W.	7440
ANSI standard (US & Canada). Dual-filament wedge bulb (T25). 12V, 27W/7W.	3157
ANSI standard (US & Canada). Single-filament wedge bulb (T25). 12V, 27W.	3156

Other Locations

Additional Notes

The Cadillac Escalade backup light specifications cover model years 1999-2014 and 2023, drawing from three distinct bulb types across that span: the 921, 7440, 3157, and 3156.
The 7440 is the most frequently specified backup light bulb across the Cadillac Escalade lineup, covering the 2007-2014 model years.
The 7440 is a single-filament T20 wedge bulb rated at 12V and 21W, conforming to ANSI standards recognized in both the United States and Canada.
The 3157 is a dual-filament T25 wedge bulb rated at 12V with a 27W main filament and a 7W secondary filament, also meeting ANSI standards for the US and Canada. It is specified for the Cadillac Escalade from 2002-2006.
Although the 3157 and 3156 share the same T25 wedge form factor and 12V/27W primary rating, the 3156 is a single-filament bulb while the 3157 carries a second filament. This distinction makes the two bulbs non-interchangeable in applications where dual-filament functionality is required.
The 3156 single-filament T25 wedge bulb is specified for the 1999-2000 Escalade model years.
The 921 is a T15 wedge bulb rated at 12V and 16W, conforming to ANSI standards. It is the specified backup light bulb for the 2023 Cadillac Escalade, and at 16W it operates at a lower wattage than any other bulb type listed in these specifications.
The T15, T20, and T25 designations refer to the bulb's tubular envelope width in eighths of an inch, meaning a T20 bulb is 20/8 inches wide. Despite all three types using wedge bases, their differing envelope sizes affect physical fitment in the socket.
All four bulb types in these specifications operate at 12V, which is consistent with standard automotive electrical systems. Wattage, however, varies from 16W to 27W depending on the bulb, which affects current draw and heat output.
The shift from the dual-filament 3157 to the single-filament 7440 between the 2006 and 2007 Escalade model years represents a change in socket and wiring compatibility, meaning the two bulbs are not interchangeable despite both being wedge-base designs.