Join Date: Jul 2007
Location: New Zealand
I used to let the well-meaning folk at the Warrant Of Fitness test station make the adjustments, but frequently I'd discover that although the height would be right, the horizontal aim was often way off. Sometimes both headlights would be pointing out into the road, but often they would be cross-eyed.
So now I just drive up to my garage door and stick some masking tape in the centres of the dipped beam patterns - the bit where the angled top meets the horizontal cutoff. Then I back up about five metres (the most flat driveway I have) and see where the beam centres go. They should stay the same distance apart and they should drop by about 1%. That is, 1% of five metres, or 5cm.
I use a measuring tape to check the distance between the beam centres - the distance between should match the distance between the lights on the car (measured to about the centre of the projector lenses).
By moving the car forwards and backwards, I can ensure that the beams are not moving side-to-side (i.e. that they are pointing straight ahead) and also that one beam is not dropping more than the other.
The headlights in my yellow Spider are a delight - I'm not sure why they are so bright, but certainly cleaning them and correctly aiming them made a big difference. Just never try to clean the silvered bits... I learned that the hard way.
'00 GTV V6, '08 FIAT 500, shell and parts for a '71 FIAT 850 Coupe