Can anyone tell me how to operate front spot lamps. I can only flash them. Regards TOG
These front lamps were fitted to allow quick flashing without having to wait for the head lamps to be raised, and they also can be used to assist the main beam so they will automatically come on with the main or high beam provided the driving lamp switch is engaged. This makes them legal as they extinguish when dipped beam is selected. In many countries, certainly the UK, they are too low to be used legally with dipped beam or instead of dipped beam in normal conditions. Lamps below 24 inches (centre of lamp) can only be used in Fog or Falling snow.
There are (or used to be) three types of additional lamps - Fog lamps, Spot lamps and Driving lamps.
Fog lamps have a short range but a very wide area to pick out the edges of the road and a flat top to the light pattern to reduce back dazzle. In fog you are driving slowly so you don't need the long range and it is more important to see the edges.
Spot lamps have a long range but a very narrow beam, to penetrate to the distance - a so called 'pencil beam'. These could be set to pick out specific things depending on the drivers preferences. So you might have it set to illuminate the white lines, or road signs etc.
Driving lamps are a sort of mix of the two - reasonably long range (but shorter than spots) to assist the headlamps to allow you to see further, but have a wider beam than spot lamps so a pair would cover the whole width of a two lane road and some of the sides.
When the glass was used to control the beam patterns, the fog lamps were heavily fluted, whilst spot lamps were almost clear glass. Driving lamps were slightly fluted. The choice of colour is historical and as I said in the thread on head lamps, white is best. Yellow simply reduces the light output which is the last thing you want. The reason yellow was chosen particularly in France, was simply that in the old days the beam pattern was not so well controlled, so by reducing the amount of light output you reduced the possible glare! Today with well controlled beams, forget yellow as it simply reduces the lamps effectiveness.
I recently bought another Espace Quadra as you may have seen in the Espace section. When I collected it, the previous owner had fitted yellow head lamps and the vision at night was pathetic. I have since changed it back to white and it is now as good as my other Quadra. Yellow head lamps and fog lamps are now purely for show!
Roy