2008 Prius Touring package 6. Last night the driver's side headlight went out coming home. In the driveway I turned off the car, turned it back on and tried the headlights. The light came back on. My guess (coming based only on experience with warehouse CFLs and ballasts) is it's more likely the ballast as opposed to the bulb itself. That said, Should I just go ahead and replace both the ballast AND the bulb? I'm also toying with replacing the entire headlight assembly since it appears to have a lot of condensation building inside of it. Visible water drops on the inside of the lens. I reviewed some online videos and can handle the ballast and/or bulb replacement but I'll probably take it in to the mechanic if you think I should replace the entire assembly.
I'm not sure what effect condensation has on either the ballast or the bulb, but I think it is safe to say that most people with intermittent HID headlight problems have found that replacing the bulb solves them. That has been my experience, 2007 Headlight dead even after OEM replacement | PriusChat, but then again I did not see any condensation on the inside of my headlight assembly.