Cadillac CTS front side marker bulbs use 168 or 194 size, while rear side marker bulbs require 12961 size. The chart covers 2003 through 2019 with replacement bulb size specifications for each production year.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The front side marker position on the Cadillac CTS uses two distinct bulb sizes across its model years: the 194 for 2003-2013 and the 168 for 2017-2019.
Both the 168 and 194 are ANSI-standardized miniature wedge bulbs sharing the T10 form factor and a 12-volt operating voltage, which places them in the same physical bulb family.
Despite their shared T10 form factor, the 168 and 194 are not rated at the same wattage. The 168 draws 4.9 watts while the 194 draws 3.78 watts, meaning they are not interchangeable without a wattage difference being introduced into the circuit.
The 12961 is designated by a Philips part number rather than an ANSI standard number, indicating it is a manufacturer-specific designation rather than a universal industry code.
The 12961 bulb also carries the T10 form factor with a W2.1x9.5d base and operates at 12 volts, rated at 5 watts, making it the highest-wattage bulb among the three types listed in these specifications.
The rear side marker position on the Cadillac CTS is covered only for model years 2003-2007, all of which use the 12961 bulb.
The W2.1x9.5d base designation on the 12961 refers to a specific wedge base standard used in miniature automotive bulbs, where the numeric values describe the base width and pin spacing in millimeters.
The front side marker specification for the 2014-2016 model years is absent from the dataset, with the data moving directly from 2013 to 2017.