2018 Cadillac CT6 bulb fitment uses LED lighting for both the low-beam and high-beam headlights. The supplied fitment data does not list a replaceable bulb code for either headlight, so confirm the factory lamp assembly and service requirements before ordering a replacement.
Other exterior lighting is also LED-equipped, including the front turn signals, brake lights, center stop light, daytime running lights, license plate lights, parking lights, front and rear side markers, tail lights, and rear turn signals. No fog-light bulb fitment is listed.
- Reverse light: 921
- Trunk light: 194 or 7441
- Vanity light: 6612F
Because the CT6 uses LED lighting across most listed exterior functions, the reverse, trunk, and vanity lights are the primary locations with specified replaceable bulb numbers in this data. Verify the existing bulb and socket where multiple trunk-light options are shown.