Do I need to wire these separately or do they plug into the factory harness?

These are designed as direct bolt-in replacements that use your truck's factory headlight connector. Your vehicle's existing DRL wiring will control the LED elements — no extra harness needed.

Will the black housing need paint or sealant before I install them?

The composite housing comes finished and ready to bolt on. If you want to match custom paint or protect the finish further, you can prep and clear-coat them first — but that's optional for a stock look.

What happens if one LED element stops working after I buy them?

Check the return and warranty policy in your order confirmation. Most LED headlight assemblies have a stated coverage window — start there if you experience failure within the protected period.