m0nkey

My driver side headlights have been out for about two weeks, now and i finally just received my new bulbs (6000k). And after i put the new bulbs on only the passenger side lights up. I switch the bulbs from the passenger to the driver side and it still didnt turn on. I also checked the fuse's already. Can it be the ballast or wiring harness? Or where can i check to see where the problem is located at. Thanks