I found something very interesting (to me, anyway) when I first put a used '02 S40 on the road. The headlight adjusters were broken on one lamp and I purchased a replacement at a pullapart yard. At the same time I harvested a bunch of bulbs. All the bulbs were the same. This is the first Volvo we've owned that had anything other than sealed beams so was surprised to learn the difference between high and low beam was solely due to reflector shape. - Dave