For the 2006 Cadillac CTS, headlight bulb fitment depends on the factory headlight system. Models with halogen headlights use a 9006XS low-beam bulb, while models with HID headlights use a D1S low-beam bulb. The high-beam bulb is 9005XS.
Other notable exterior lighting sizes include:
- Front turn signals: 3157, 2825, or 98, depending on the application.
- Rear turn signals and reverse lights: 3157.
- Brake and tail lights: 3157R.
- Center stop light, dome light, and map light: PC175.
- Front side marker: 194NA.
- License plate, parking, and rear side-marker lights: 2825 or 98.
Verify whether the CTS has halogen or HID headlights before ordering the low-beam bulb. The supplied fitment data does not list a fog-light bulb for this model year.