Do I need to run new wiring or can I tap into existing circuits?

These are designed with plug-and-play wiring. You can integrate with factory harnesses or run independent circuits — either way, the switch gives you standalone control at the dash.

Will these fit in the OEM fog light pockets without any trimming?

Yes. They mount at factory mounting points with zero cutting or modification. Test-fit before final fastening to confirm clearance in your truck's bumper trim.

Do bulbs come with these or do I need to buy them separately?

Bulbs are not included. Pull the exact bulb spec from your truck's service manual or the product packaging once you receive it, then source them separately.