It is not uncommon for the exterior light bulbs to burn out prematurely. No repair option has been reported other than replacing the failed bulb.Google+
Car Problem Reports
Volvo S80 Exterior Light Bulbs May Burn Out Prematurely
Volvo S80 Problem
Average Mileage: 110,543 mi (45,343 mi - 163,000 mi)
Visitor, 2004 Volvo S80
Replaced front headlights twice. They cant seem to stay on.
Visitor, 2008 Volvo S80, 78,000 mi
this is the fourth time that i had to replace low lights it's getting to be a pain already!!!!!!!
Visitor, 2001 Volvo S80, 121,000 mi
Bulbs continue to burn out about every 3 months
Visitor, 2000 Volvo S80, 125,000 mi
Replace headlight bulbs frequently
I have replaced the headlights 6 times in the last 9 months. Now it is more than replacing the bulb. A new bulb does not work