What Size Bulbs Does a 2003 Cadillac CTS Use?
Correct headlight, fog light, and tail light bulb sizes. Sourced from OEM catalog data.
Installation Difficulty
Easy (Plug and Play)
Est. Replacement Cost
$50 - $150 (HID System)
What Lighting System Does the 2003 Cadillac CTS Have?
Lighting on the 2003 Cadillac CTS is managed by a total of 15 bulbs, covering everything from primary headlights to signal indicators. It features an extensive lighting system powered by premium factory HID/Xenon technology utilizing D1S projector housings for high-intensity output. This model belongs to the early years of the CTS's 2003-2019 production span.
Can You Put LED Bulbs in a 2003 Cadillac CTS?
The 2003 Cadillac CTS is already equipped with factory D1S 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 9145 LED fog lights are typically halogen and are excellent candidates for an LED upgrade to match the color temperature of your HID headlights.
2003 Cadillac CTS Bulb Size Chart
| Position | Bulb Size | Shop |
|---|---|---|
| Low Beam | HID-D1S LED | Buy HID-D1S LED → |
| High Beam | 9005XS LED | Buy 9005XS LED → |
| Fog Light | 9145 LED | Buy 9145 LED → |
| Brake Light | PC175 LED | Buy PC175 LED → |
| Side Marker | 2825 LED | Buy 2825 LED → |
| Turn Signal Front | 2825 LED | Buy 2825 LED → |
| Turn Signal Rear | 3157K LED | Buy 3157K LED → |
| Dome Light | PC175 | Buy PC175 → |
| License Plate | 2825 | Buy 2825 → |
| Map Light | PC175 | Buy PC175 → |
| Parking Light | 2825 | Buy 2825 → |
| Reverse Light | 3157K | Buy 3157K → |
| Trunk Light | 211-2 | Buy 211-2 → |
| Daytime Running | 3157 | Buy 3157 → |
| Tail Light | 3157CK | Buy 3157CK → |
How do the 2003 Cadillac CTS's bulbs compare to other years?
The 2004 model continues with the same bulb sizes.
This bulb configuration covers the 2003–2004 model years. 2004 →
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