I have a 2004 XC70 with 286,000 miles. I have factory installed HID Xenon head lamps. The driver side bulb just burned out, so I replaced it with a new D2R that cost $100. It worked for minutes or hours and then burned out. I took it back to the parts store and they told me I probably had a bad ballast and that if I replaced the bulb again it would just blow again. Where is the ballast, how much does it cost, and how to replace it.

 

I hope its not too late to tell you where to find the parts for MUCH less than the dealership or parts houses. HIDconcepts.com has the ballast for $85 or so as opposed to Volvo's IDENTICAL part for $300! Look on eBay for bulbs too. I've had mine in for over a year and paid a fraction of the cost. All brands are there too.

 

BTW: The ballast is behind the front bumper! There's one for each bulb. So much for efficient Swedish engineering!

 

Does this mean the front bumper has to come off as another reply indicated??

 

Yes. To get at the ballast resistor, the bumper needs to be removed.