I'm having a similiar issue with some OEM HID's I installed in a '04 WRX, where the driver side comes on fine, but the passenger side flickers and never activates (I've never left it on for more than 10 seconds since I don't want to burn out the ballast). I've disabled the DRLs, and have ground straight back to the battery. I know the ballast is good, because I can plug the passenger side into the driver side and it works great. In my troubleshooting, I noted that if I leave the connector to the small upper bulb (between the low and high beams) unplugged, the passenger side won't do anything, but the driver side works fine! Any thoughts as to what might be going on?