What Size Bulbs Does a 2018 Cadillac XTS Use?
Correct headlight, fog light, and tail light bulb sizes. Sourced from OEM catalog data.
Installation Difficulty
Moderate (Dust covers often present)
Est. Replacement Cost
$15 - $40 (Halogen) / $30+ (LED)
What Lighting System Does the 2018 Cadillac XTS Have?
The 2018 Cadillac XTS features an extensive lighting system with 12 bulb positions. It uses factory LED technology with integrated LED headlight modules. The XTS has been available from 2013 to 2019, and the 2018 model falls in the late-generation years.
Can You Put LED Bulbs in a 2018 Cadillac XTS?
Upgrading the 2018 Cadillac XTS to LED headlights is straightforward since it uses a single LED Headlights dual-filament bulb for both low and high beams. You only need one pair of LED bulbs to upgrade both functions. Look for a LED Headlights LED kit that specifically supports dual-filament operation to ensure both beams work correctly. For the fog lights, a LED Fog Light LED bulb provides a clean white output that pairs well with LED headlights.
How to Replace Bulbs on a 2018 Cadillac XTS
To remove the headlight bulb, disconnect the wiring harness, then twist the bulb counter-clockwise and pull it straight out of the housing. On the 2018 XTS, you will likely encounter rubber dust covers behind the headlight housing. These pull off by hand or unscrew depending on the design. Allow about 15 to 20 minutes per side. This vehicle has factory-integrated LED headlight modules. These are not user-serviceable bulbs. If your LED headlights fail, the entire headlight assembly or LED module may need to be replaced by a dealer or qualified technician. The fog lights are accessed from underneath the front bumper. You may need to remove a few plastic clips or screws from the fender liner to reach the LED Fog Light fog light socket.
Full Upgrade Bundle
Upgrade All 12 Positions at Once
2018 Cadillac XTS Complete Bulb Size Chart
| Position | Bulb Size | Shop |
|---|---|---|
Low Beam | LED Headlights | Buy LED Headlights |
High Beam | LED Headlights | Buy LED Headlights |
Fog Light | LED Fog Light | Buy LED Fog Light |
Brake Light | LED Bulb | Buy LED Bulb |
Side Marker | LED Bulb | Buy LED Bulb |
Turn Signal Front | LED Bulb | Buy LED Bulb |
Turn Signal Rear | LED Bulb | Buy LED Bulb |
License Plate | 2825 | Buy 2825 |
Map Light | LED Bulb | Buy LED Bulb |
Parking Light | LED Bulb | Buy LED Bulb |
Reverse Light | 921 | Buy 921 |
Trunk Light | 175 | Buy 175 |
Want to upgrade everything at once?
Shop Complete LED Kit for 2018 Cadillac XTSHow Long Do 2018 Cadillac XTS Headlight Bulbs Last?
Factory LED headlights on the 2018 Cadillac XTS are rated for approximately 25,000 to 50,000 hours of use, which translates to roughly 10 to 15 years of normal driving. LED modules rarely burn out suddenly. Instead, they gradually dim over time or develop dead zones within the LED array. At 8 years old, the original bulbs on your XTS are likely overdue for replacement, though LED modules may still have life left. Even if they still illuminate, reduced brightness significantly impacts nighttime safety. When one headlight burns out, replace both sides at the same time. Bulbs from the same batch age at similar rates, and mismatched brightness is distracting to oncoming drivers.
What Bulbs Are Compatible with the 2018 Cadillac XTS?
Using the wrong bulb size can cause improper beam patterns that reduce your visibility and blind other drivers. It can also cause overheating inside the headlight housing, potentially warping the plastic lens or reflector. Always verify the bulb number before purchasing.
2018 Cadillac XTS Headlight FAQ
Did Cadillac XTS Bulb Sizes Change Over the Years?
Over its production run from 2013 to 2019, the Cadillac XTS has seen bulb size changes in the Low Beam, High Beam and Turn Signal Front positions. The 2018 model uses the newer bulb specification introduced around 2018. Always verify the exact bulb size for your specific 2018 model year using the chart above, as using the wrong size can result in poor fitment or reduced light output.