Hi Scotty, I have a 2007 Toyota Prius with HID headlamps and 125,000 miles. Over the past 2 years, only the passenger side headlight has gone out at times. I have just turned the headlamp switch off and then on again and it turns that headlamp back on again. However, that no longer works as of today. Do I just need to replace that HID bulb ($50) or do I also need to replace the ballast ($80) as well?