Cadillac CTS 2003 Bulb Size
Bulb size chart
This 2003 Cadillac CTS bulb size guide helps you verify the correct bulb by lighting position, so you can replace a failed lamp with the right fit the first time. Whether you are working on the headlights, tail lamps, interior lights, or small exterior markers, this page organizes the bulb chart by location for easier lookup.
The 2003 Cadillac CTS used different bulb types depending on the light position, and some setups can vary by trim, market, or lighting package. Use this page to match the bulb to the exact spot on the car, such as low beam, high beam, brake light, parking light, or dome light, before you buy replacements.
Fitment can vary on the 2003 Cadillac CTS, especially between halogen and HID headlight setups and between different trim or package combinations. If your car has halogen low beams, the listed bulb is 9006XS, while HID-equipped cars use D1S for low beam; the high beam uses 9005XS. LED upgrades and aftermarket conversion kits may fit physically but still need to match the housing, connector, and beam pattern, so it is smart to compare the installed bulb before ordering. For the best result, remove the old bulb and confirm the number printed on it, since that is the most reliable way to avoid a mismatch.
FAQ
What is the low beam bulb for a 2003 Cadillac CTS?
The low beam bulb depends on the headlight system. A 2003 Cadillac CTS with HID headlights uses D1S low beam bulbs, while a CTS with halogen headlights uses 9006XS low beam bulbs.
What bulb does the high beam use on the 2003 Cadillac CTS?
The high beam bulb is 9005XS on the 2003 Cadillac CTS.
Which bulb fits the brake light on this CTS?
The brake light bulb listed for the 2003 Cadillac CTS is 3157R.
Are the tail light and brake light bulbs the same?
Yes, the bulb chart lists 3157R for both the tail light and brake light positions on this model year.
What bulb is used for the daytime running light?
The daytime running light bulb for the 2003 Cadillac CTS is 3157.
What is the rear turn signal bulb size?
The rear turn signal light bulb is 3157 on the 2003 Cadillac CTS.
What bulb fits the front outer turn signal?
The front outer turn signal light bulb is 2825, 98.
What bulb is used for the front inner turn signal?
The front inner turn signal light bulb is 3157.
What is the side marker bulb size on the front of the car?
The front side marker light bulb is 194NA.
What bulb fits the license plate lights?
The license plate light bulb is 2825, 98 on the 2003 Cadillac CTS.
What bulb is used for the parking lights?
The parking light bulb is 2825, 98.
What bulb fits the reverse lights?
The back up reverse light bulb is 3157.
What is the center high mount stop light bulb?
The center high mount stop light bulb is PC175.
Which bulb is used for the dome light and map light?
Both the dome light and map light use PC175 bulbs on this vehicle.
What bulb fits the trunk or cargo area light?
The trunk or cargo area light uses a 211-2 bulb.
What bulb is listed for the courtesy light?
The courtesy light bulb is 564.
Can trim or lighting package changes affect bulb fitment?
Yes. Trim, market, and lighting package differences can change the exact bulb setup, especially for headlights and some exterior lamps, so it is important to verify the installed bulb and the lighting configuration on your specific CTS.