Volvo S80 No Headlights? How to Fix.
Volvo S80 low beam headlights not working? How to fix.
First check the fuses and the bulbs. Note this picture of the circuit panel. Remove the panel under the drivers side dash and look for a burned spot where the small black shunt board goes. You can sand or scrape the spade connector but cleaning the contact in the board is a bit tricky. One way is to take a thin strip of metal, rough it up and insert it into the panel working it back and forth. Use a little grease on the contact to reduce oxidation that starts the process again.
The picture shows you where to look for a burned spot.