What Size Bulbs Does a 2007 Cadillac STS 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 2007 Cadillac STS Have?
The 2007 Cadillac STS features an extensive lighting system with 13 bulb positions. It uses factory HID/Xenon technology with D1S projector headlights. The STS has been available from 2005 to 2011, and the 2007 model falls in the mid-generation years.
Can You Put LED Bulbs in a 2007 Cadillac STS?
The 2007 Cadillac STS comes equipped with factory D1S HID/Xenon headlights. These already produce significantly more light than halogen bulbs, so upgrading is generally unnecessary. When your HID bulbs burn out, replace them with OEM-spec D1S HID bulbs to maintain the correct color temperature and beam pattern. Avoid cheap aftermarket HID bulbs as they can produce incorrect beam patterns and blind oncoming drivers. Your fog lights use a H3 LED halogen bulb, which can be upgraded to LED for a whiter color match with your HID headlights.
How to Replace Bulbs on a 2007 Cadillac STS
To remove the headlight bulb, disconnect the wiring harness, then twist the bulb counter-clockwise and pull it straight out of the housing. Older model years like the 2007 STS typically offer easy access to the headlight bulbs from behind the headlight assembly under the hood. Most owners can complete the swap in under 10 minutes per side. HID headlights operate at high voltage. Always disconnect the battery before working on the headlight assembly. Never touch the HID ballast while the headlights are on, and handle the D1S capsule with gloves to avoid oil contamination. 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 H3 LED fog light socket.
Full Upgrade Bundle
Upgrade All 13 Positions at Once
2007 Cadillac STS Complete Bulb Size Chart
| Position | Bulb Size | Shop |
|---|---|---|
Low Beam | HID-D1S LED | Buy HID-D1S LED |
High Beam | 9005 LED | Buy 9005 LED |
Fog Light | H3 LED | Buy H3 LED |
Brake Light | PC175 LED | Buy PC175 LED |
Side Marker | 2825 LED | Buy 2825 LED |
Turn Signal Front | 3757AK LED | Buy 3757AK LED |
Turn Signal Rear | LED Bulb | Buy LED Bulb |
Dome Light | 212-2 | Buy 212-2 |
License Plate | 2825 | Buy 2825 |
Map Light | PC175 | Buy PC175 |
Parking Light | 3757AK | Buy 3757AK |
Reverse Light | 3157KX | Buy 3157KX |
Trunk Light | LED Light | Buy LED Light |
Want to upgrade everything at once?
Shop Complete LED Kit for 2007 Cadillac STSHow Long Do 2007 Cadillac STS Headlight Bulbs Last?
HID/Xenon headlights on the 2007 Cadillac STS typically last 2,000 to 3,000 hours, or about 4 to 6 years of regular driving. As HID bulbs age, they shift color toward pink or purple, which is a clear sign that replacement is needed. Flickering on startup also indicates a worn bulb or failing ballast. At 19 years old, the original bulbs on your STS are likely overdue for replacement. 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 2007 Cadillac STS?
For the high beams, the 9005 is interchangeable with HB3. 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.
2007 Cadillac STS Headlight FAQ
Did Cadillac STS Bulb Sizes Change Over the Years?
Over its production run from 2005 to 2011, the Cadillac STS has seen bulb size changes in the Brake Light, Dome Light and Trunk Light positions. The 2007 model uses the earlier bulb specification that was in place before the change around 2010. Always verify the exact bulb size for your specific 2007 model year using the chart above, as using the wrong size can result in poor fitment or reduced light output.
Other STS Years
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Other Vehicles That Use HID-D1S LED Bulbs
These vehicles from other makes also use a HID-D1S LED low beam bulb: