For the 2015 GMC Terrain, the low-beam headlight uses an H11 bulb, while the high beam and daytime running light use 9005. The fog-light fitment is listed as either H11 LED or H16 LED, so verify the existing fog-light application before ordering.
Other useful exterior fitments include 7444NA for the front turn signal and parking light, 194NA for the front side marker, and 921 for the reverse light. The rear turn signal uses 3057, while the brake light is 3057R. The center stop light is an integrated LED unit.
Interior and auxiliary bulb options include 2825 or 98 for the dome and map lights, 194 or 7441 for the glove-box and trunk lights, and 6612F for the vanity light. License-plate lighting is listed as 2825 or 98. Confirm the bulb currently installed where multiple options are shown.