2018 GMC Sierra Headlight Bulb Size
Low beam
9012
High beam
9012
Order
2 × 9012
Your 9012 uses one bulb per side that handles both low and high beam — a dual-filament 9012. Two bulbs covers the whole front end.
This is the last year that uses 9012/9012, which started in 2014. See all Sierra years.
2018 GMC Sierra bulb chart
| Position | Bulb | Notes |
|---|---|---|
| Low beam | 9012 |
Shared with high beam — one bulb does both. |
| High beam | 9012 |
Same bulb as low beam. |
Verified against factory service data and OEM bulb references.