Not the bulbs. Ballast is the issue. Unless there are signs of the harness being an issue.I also have a 2001 Lexus is300 and I am going through the same issue. My running lights will stay on for about 30 seconds to a minute. And the high beams stay on so I can only use them or I have to keep turning the running lights on and off. Anyone have a solution maybe the ballast and bulbs?