Do these bolt straight to my existing headlight brackets?

These are designed for factory mounting points—they use the same anchors as your OEM lights. No drilling or fabrication needed for install.

Does the switchback function work without any extra wiring harness?

The switchback design handles the color shift internally. Your existing turn signal wire triggers the amber output—no additional relays or modules required.

Will these headlights work with my truck's stock electrical, or do I need to upgrade the harness?

They're engineered to work with your vehicle's factory harness and wiring. LED draw is lower than incandescent, so your existing setup supports them without modification.