Cadillac XTS Back Up Light Bulb Size

The Cadillac XTS back up light utilizes a 921 bulb size for illumination purposes within the rear lighting assembly. Provided information covers a span of time starting in 2013 and ending in 2019.

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
2013-2019	921

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Wedge bulb (T15). 12V, 16W.	921

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Additional Notes

The Cadillac XTS uses the 921 bulb for the back up light across all model years from 2013-2019.
The 921 is an ANSI-standardized bulb type, meaning its specifications are governed by a recognized North American standard shared across the United States and Canada.
The 921 belongs to the T15 form factor, which refers to a wedge-style base. A wedge base has no metal pins; instead, the glass envelope itself is pinched at the bottom and pressed directly into the socket.
The bulb operates at 12 volts, consistent with the standard electrical system voltage found in conventional passenger vehicles.
The 921 carries a 16-watt power rating, which reflects the amount of electrical power the bulb draws during operation.
Because the 921 follows the ANSI standard, it is subject to defined tolerances for physical size and electrical performance, which supports interchangeability among compliant 921 bulbs from different manufacturers.