Every now and then one of the HID headlights goes out on our 2006 Prius, seems to be a random event not favoring either headlight. Shutting the headlights off, then turning them back on again corrects the issue. The problem with using this fix is that it isn't good for the HID bulb. Anyone have a better solution?
Known issues. Like patrick said, replace bulbs. LOTS of threads on how to do it yourself and what to buy.
It's the ballasts. I did some digging before I found the right answer. Change the ballast and the problem should be fixed.