Vauxhall Vectra headlights

sounds odd that low beam is bad but high is good.. however on the vectra the low beams are on one pair of bulbs and the mains are on another... if you can look at the bulbs whilst they are on youll see if the filiment is orange or a blurred very bright yellow.. check the seat they are in and see if the earth needs sorting.. also check you connections , give it the wire wiggle test to make sure your circuit is good.. other than that .. try new low beams, halogens best ... if the whole headlight is dull its creamed... whole new topic but can be sorted.. hope this helps you..ok

That is normal on these cars as the headlights use a projector lense that does not work very well. People have improved the light vision by using night breaker bulbs or even fit HID'S.