What is the low beam headlight bulb size for a 2018 Cadillac CTS?

The 2018 Cadillac CTS uses a HID-D3S LED bulb for the low beam headlights. We recommend upgrading to LED for better visibility.

What is the high beam headlight bulb size for a 2018 Cadillac CTS?

The high beam bulb size for the 2018 Cadillac CTS is HID-D3S LED.

Why are my 2018 Cadillac CTS headlights dim?

Dim headlights on a 2018 Cadillac CTS can be caused by aging halogen bulbs, which lose brightness over time, or oxidation (cloudiness) on the plastic headlight lenses. Upgrading to a HID-D3S LED LED conversion kit can provide a significantly brighter and whiter light output.

Which bulb fits the 2018 Cadillac CTS fog light?

The 2018 Cadillac CTS uses a LED Fog Light bulb for the fog light position.

Is the 2018 Cadillac CTS single or dual beam?

The 2018 Cadillac CTS uses a single bulb (dual filament) headlight system. This means one bulb controls both high and low beams.

Can I install LED bulbs on my 2018 Cadillac CTS?

Yes, the 2018 Cadillac CTS comes with standard halogen bulbs from the factory, but they can be upgraded to LED. You will need a HID-D3S LED LED conversion kit for the low beams.

Does the 2018 Cadillac CTS have fog lights?

Yes, the 2018 Cadillac CTS takes a LED Fog Light bulb for the fog light position.

Did the 2018 Cadillac CTS change headlight bulb sizes from the previous year?

No — the 2018 Cadillac CTS uses the same bulb sizes as the 2017 model. This configuration has been consistent across the 2016–2019 generation.

How do I change the headlight on a 2018 Cadillac CTS?

Turn off the vehicle and open the hood. Locate the headlight assembly from behind, remove the dust cover or retaining clip, disconnect the wiring harness, twist the old HID-D3S LED bulb counter-clockwise to remove it, then insert the new bulb and reassemble. The whole process typically takes 10 to 30 minutes per side depending on accessibility.

Are LED headlights legal for a 2018 Cadillac CTS?

LED bulbs used off-road or in auxiliary lights are legal everywhere. For on-road headlight use, legality varies by state. Many states allow LED retrofits as long as the beam pattern meets DOT standards. For the best legal compliance, choose a DOT-approved HID-D3S LED LED kit that is designed as a direct replacement and produces a proper cutoff pattern without excessive glare.

How much does it cost to replace 2018 Cadillac CTS headlights?

A pair of HID HID-D3S LED bulbs costs $50 to $150. If you have a shop do the work, expect an additional $20 to $50 in labor per bulb. Replacing them yourself at home saves the labor cost and usually takes under 30 minutes.

What is the difference between halogen and LED for a 2018 Cadillac CTS?

Halogen bulbs produce a warm yellow light (around 3200K), last 500 to 1000 hours, and draw more power. LED bulbs emit a brighter white light (5000-6000K), last 25,000+ hours, and use less energy. LED upgrades for the HID-D3S LED position are available as direct plug-and-play replacements.

The 2018 Cadillac CTS shares its bulb sizes with the 2016–2019 generation.

Fitment Guaranteed for 2018 Cadillac CTS

What Size Bulbs Does a 2018 Cadillac CTS 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

$50 - $150 (HID System)

What Lighting System Does the 2018 Cadillac CTS Have?

Lighting on the 2018 Cadillac CTS is managed by a total of 14 bulbs, covering everything from primary headlights to signal indicators. It features an extensive lighting system powered by premium factory HID/Xenon technology utilizing D3S projector housings for high-intensity output. This model belongs to the late years of the CTS's 2003-2019 production span.

Can You Put LED Bulbs in a 2018 Cadillac CTS?

The 2018 Cadillac CTS is already equipped with factory D3S HID/Xenon headlights. Since HID technology already provides exceptional brightness, we recommend staying with high-quality OEM replacement bulbs rather than attempting an LED retrofit for the primary headlights. However, the LED Fog Light fog lights are typically halogen and are excellent candidates for an LED upgrade to match the color temperature of your HID headlights.

2018 Cadillac CTS Bulb Size Chart

Position	Bulb Size	Shop
Low Beam	HID-D3S LED	Buy HID-D3S LED →
High Beam	HID-D3S LED	Buy HID-D3S LED →
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 →
Dome Light	2825	Buy 2825 →
License Plate	2825	Buy 2825 →
Map Light	PC175	Buy PC175 →
Parking Light	LED Bulb	Buy LED Bulb →
Reverse Light	921	Buy 921 →
Trunk Light	211-2	Buy 211-2 →
Door Light	906	Buy 906 →

How do the 2018 Cadillac CTS's bulbs compare to other years?

The 2018 Cadillac CTS uses the same bulbs as the 2017 model.

The 2019 model continues with the same bulb sizes.

This bulb configuration covers the 2016–2019 model years. ← 2017 2019 →

Finding the best installation guide...

Other CTS Years

2019 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003

More from Cadillac

60 Special ATS Allante Brougham CT6 CTS Coupe & Wagon CTS Sedan CTS-V Sedan

Other Vehicles That Use HID-D3S LED Bulbs

2023 Chevrolet Camaro 2022 Dodge Charger 2022 Dodge Durango 2022 Hyundai Ioniq 2022 Kia Sportage 2021 Dodge Challenger