For the 2013 GMC Sierra 2500HD, the low-beam headlights use H11 bulbs, while the high-beam headlights use 9005 bulbs. The supplied fitment data does not identify separate headlight variations, so verify the existing bulb and housing before ordering.
The fog lights use 5202 LED bulbs, and the daytime running lights use H11 LED bulbs. At the front, the turn signals and parking lights use 4157NA, while the front side markers use 194NA.
For rear lighting, the reverse lights use 3047 bulbs, the brake and tail lights use 3047R, and the rear turn signals also use 3047. The center stop light uses 921. Other useful replacements include 168 for the license plate lights, 212-2 for the dome and map lights, 912 for the trunk light, and 6612F for the vanity light. Match the bulb designation and lighting position carefully when replacing bulbs.