The most common setup on a 2015 GMC Sierra with halogen headlights uses H11 for low beams, 9005 for high beams, and H11 for fog lights. If your truck has HID or LED headlights, that arrangement is different and you’ll need the specific bulb type for that package.
Bulb sizes vary by trim and whether the vehicle is equipped with halogen, HID, or LED lighting. This article provides the typical sizes you’ll encounter and how to confirm the exact bulb type for your particular Sierra.
Typical exterior bulb sizes
Below are the bulb sizes you’re most likely to encounter on a 2015 Sierra with standard halogen headlights. Use this as a quick reference, but verify against your exact build.
- Low beam (headlights): H11
- High beam (headlights): 9005
- Fog lights: H11
Note: If your Sierra uses HID or LED headlights, these sizes do not apply. HID systems use ballast-supported bulbs, and LED setups use a different module or bulb type specified for that trim. Always verify with the owner’s manual or GM’s official parts diagrams for your exact vehicle.
How to confirm your exact bulb size
Because bulb sizes can vary by trim and lighting package, the following steps help ensure you get the correct replacement.
- Check the owner's manual or a GM parts diagram for your vehicle’s exact bulb specification.
- Inspect the bulb directly: remove the headlight bulb and read the imprint on the base or glass if you have a halogen setup.
- Use your vehicle’s VIN in an online parts catalog to confirm the precise bulb type for your exact configuration.
- If you’re unsure, consult a professional to avoid ordering the wrong bulb, especially for HID or LED headlamps.
Using the correct bulb size prevents compatibility issues and ensures proper fitment and performance. When in doubt, verify through official GM resources or a trusted automotive technician.
Summary
For 2015 GMC Sierra models with halogen headlights, expect H11 low beams, 9005 high beams, and H11 fog lights. Models equipped with HID or LED headlights do not use these standard halogen bulbs, and the exact bulb type will differ. Always confirm with the owner’s manual, VIN-based parts lookup, or a dealership to ensure you purchase the correct bulbs for your specific vehicle.