Cadillac CTS 2018 Bulb Size
Bulb size chart
This page covers the 2018 Cadillac CTS bulb sizes by lighting position, so you can quickly match the right replacement to the right lamp. Whether you are changing an exterior signal, a reverse light, or an interior courtesy bulb, the chart is organized to help you verify fitment before you buy.
The 2018 Cadillac CTS uses a mix of LED and replaceable bulb types depending on the location, trim, and lighting package. That means the correct bulb can vary by function, so it is important to check the specific position on the vehicle instead of assuming one size fits every light.
For the best fit, compare the bulb listed for your exact lighting position with what is already installed on the car, especially if your CTS has a different trim, body style, or factory lighting package. Some exterior lamps on this model are LED assemblies, while others use serviceable bulbs, and aftermarket conversions can change the required bulb type or create fitment issues. If you are upgrading from halogen-style bulbs to LED replacements, make sure the new bulb is compatible with the housing and electrical system. When possible, inspect the old bulb before ordering so you can confirm the base style and avoid returns.
FAQ
What bulb size does the 2018 Cadillac CTS use for the headlights?
The 2018 Cadillac CTS uses a D3S bulb for both the high beam and low beam headlight function on the listed setup.
What is the reverse light bulb size for a 2018 Cadillac CTS?
The back up reverse light bulb is listed as 921 for the 2018 Cadillac CTS.
Are the brake lights on the 2018 Cadillac CTS replaceable bulbs?
The brake light bulb is listed as LED, so the brake light may be part of an LED assembly rather than a standard replaceable bulb.
What bulb size is used for the front turn signal on this CTS?
The front turn signal light bulb is listed as LED on the 2018 Cadillac CTS.
What bulb size is used for the rear turn signal on this CTS?
The rear turn signal light bulb is listed as LED on the 2018 Cadillac CTS.
What bulb size does the license plate light use?
The license plate light bulb is listed as 2825 or 98 for the 2018 Cadillac CTS.
What are the interior dome light bulb sizes?
The dome light bulb is listed as 2825 or 98 for this model year.
What bulb fits the glove box light on a 2018 Cadillac CTS?
The glove box light bulb is listed as 906.
What bulb fits the interior door light?
The interior door light bulb is listed as 906 on the 2018 Cadillac CTS.
What is the trunk or cargo area light bulb size?
The trunk or cargo area light uses a 211-2 bulb.
What bulb does the map light use?
The map light bulb is listed as PC175, and it is noted as optional on the raw list.
Do trim levels affect bulb fitment on the 2018 Cadillac CTS?
Yes. Trim and lighting package can vary by market and body style, so some bulbs may differ depending on the exact vehicle configuration.
Should I check the old bulb before ordering replacements?
Yes. Checking the installed bulb before purchase is a smart way to confirm the correct fit, especially for interior bulbs and any position that may vary by package.