Alright my passanger side light isn't coming on in my retro headlights. I swapped both ballast and headlights from passenger to driver side and they both work fine but passanger side still isn't lighting up. What could my problem be?

 

Sounds like a bulb to me

Do u have a relay harness?

 

Nevermind I figured it out. I was having a ground issue on the passanger side!