Do these mount at the factory fog light openings?

Yes, these use factory mounting points on the Civic — no cutting or drilling required. Test-fit before securing to ensure proper alignment.

Does the switch wire into the factory harness or stand alone?

The switch assembly is independent; you'll run a dedicated circuit. Exact wiring routing depends on your setup — consult a wiring diagram for your year to confirm dash and engine bay paths.

Can I replace just the bulb if one burns out later?

H3 bulbs are standard and widely available. Once installed, you can swap them out as needed — no special tools required.