Do these use the factory fog light harness?

Yes. These are direct replacements that connect to your vehicle's existing fog light wiring and switch. No rewiring or adapter harnesses needed.

Are the bulbs the right type and already installed?

The bulbs are included and ready to go. They're the correct replacement spec for this light assembly — no need to source them separately.

What if one light fails after I install it?

Test both units before final installation to catch any DOA units immediately. Once confirmed working and mounted, they're covered under standard return policy if defective.