Will these work with my factory wiring harness?

Yes. These are designed for direct plug-and-play connection to your E46's OEM electrical connector. No splicing or adapter required — they integrate with your factory headlight circuit immediately.

Do the angel eye halos turn on automatically?

The halos operate independently of your low beam and are wired to the parking light circuit, so they illuminate whenever your parking lights or headlights are on. You don't control them separately.

What if one headlight doesn't work after install?

Test power to both sides before assuming a dead bulb. A tripped fuse or loose connector at the back of the housing is the most common culprit. If one assembly is defective on arrival, reach out to ModSupply with photos and we'll move fast.