Do these lights work with factory wiring, or do I need new harnesses?

These bolt onto factory mounting points and are designed for direct connection to OEM electrical. If your original lights work, these will plug straight into the existing harnesses without adapters.

Will the clear lens yellow over time like my old lights?

These are brand new units, so they start crystal clear. UV degradation happens to all bumper lights over time — periodic cleaning keeps them looking sharper longer than neglected stock lights.

Are there any fasteners or clips included, or do I use my old hardware?

The set includes the light assemblies. Mounting hardware is not confirmed — inspect your current lights before removal to see what fasteners are already in place, then reuse or source replacements if needed.