Will I need to run new wiring or can I use the factory harness?

Factory harnesses work, but these lights don't come with a switch. If your truck has fog light wiring already, you can tap into it. If not, you'll need a relay harness—most guys grab a simple 40-amp relay kit and run power from the battery. Depends on what you've got under the hood.

Do these bolt straight into the existing fog light buckets?

Yes. They mount at factory points with no drilling or bracket fabrication required. Test-fit before you tighten everything down to make sure the lens sits flush.

What if I need to brighten or refocus the beam after install?

Most fog lights have internal aiming adjusters. Once they're bolted in place, you can fine-tune the beam direction slightly. If the output feels weak, check that your power supply is solid—low voltage kills brightness faster than anything else.