Do these come with the bulbs installed?

Bulbs are not included. You'll transfer your existing bulbs from the factory housings or source compatible replacements before install.

What fasteners do I need to bolt these on?

Hardware specifics aren't listed—test-fit the assemblies first, then reference your vehicle's service manual or Silverado/Avalanche forum for the exact fastener count and torque specs.

Will the wiring connect straight to my factory harness?

These are designed for plug-and-play wiring, but confirm connector compatibility before purchase. If your truck has a non-standard electrical setup, you may need an adapter.