I have been having a persistent problem with the driver side headlight low beam bulb going out. I replaced the bulb and it went out after a week. The bulb is good (it lights up off the battery). Now, when I install a good bulb it doesn't light up. I'm using Heliolite Xenon H11 halogen bulbs. The other passenger low beam, both high beams, and both parking lights are fine. I've checked the fuse (and replaced it) as well. Some times it will come, but when I shut off the car, it goes out again.

Do any relays control the fuses that affect the headlights? Is there a known issue?

This is driving me nuts!

 

In S60 listings today there is a thread about turn signal failures caused by bad sockets. I wonder if your problem isn't just another manisfestation of that problem. Only Volvo could screw up sockets! Or maybe your's is somehow corroded. I'd take a peek at that first

 

OK well I had the bright idea to change the factory Xenon bulbs on my 2004 V70 r, in an effort to possibly get more high beam light. All went well, then the drivers side went out after about an hour of use when I stopped then restarted the car. Thought maybe just a bad bulb, so I replaced with no luck. Went to Volvo dealer to see if they could check the ballast. Said no, said probably some sort of control unit for the left side light was bad. Said it was $480. Any suggestions regarding this problem? Thanks

 

There is a relay in the electric box that located right by the hood release on the driver's side. I know about this because I installed 35watt aftermarket HID's and had a dip beam alert constantly. I tried drilling a hole in the relay which solved the problem for a while and the it began burning out bulbs. I replaced the relay with a new one and installed 55watt HID lights from vvme.com. No problems since. If you do this get the 6000 or 8000 k lights. The 55 watt blubs are super bright so you might get the 6000k or 8000k There is a discussion on one the forums on this topic but I can't find it.
Find the relay and replace it first it was less than $10 from the dealer.

 

OK I'll check that out in the morning Thanks