Welcome to Volvos and the land of Dialectric Grease. Since the aging wiring and connectors are a frequent source of niggling little problems in these cars, it would be a good thing for you to go through every little wiring connection under the hood (especially all of the ones around, under, and behind the coil and PS reservoir) with some sandpaper to clean them up, and put them back together with dialectric grease. Especially, this will keep intermittent stalling and no-start conditions away. Same with the headlight connections. Follow the headlight ground and make sure the grounding point is clean and tight. The driver's side (I think) is connected to the brackets near the coil, the one with the all-important 25-amp blade fuse for the fuel pump and injection system (make sure that one is cleaned up as well). The passenger side headlight ground is behind the washer fluid reservoir. You'd better clean both sides up if one is giving you troubles.

Also, just so you know, the bulb indicator idiot light measures differences in between the bulbs from one side to the other, and it is very sensitive. So if you ever replace a bulb, you have to replace its mate on the other side (ideally with the same brand of bulb).