[Edited on 28/11/06 by GavBurns]
My car has a pair of stop & tail lights and a pair of fog lights. In the interest of safety I wish to make the fog lights double up as stop &
tail lights during good weather, with the fog light function kicking in when needed (through some basic electronics)
Does anyone know if this is going to be ok for Mr SVA?
Fog lights have a very specific beam pattern and i believe it also says in the SVA manual that the fog light must not be actuated from the brake pedal.
It would still have the same beam pattern when used as a fog light (and just as bright) but will effectively dim to the same level as the tail lights
when not required. Also it would only be operated from the brake pedal switch when in tail light mode.
[Edited on 4-12-06 by RazMan]
am sure that there is a distance that stop/tail lights have to be from the fog lamp ??
About ten years ago I had a 16v Astra GTE and I connected the foglights to the brake lights and got pulled by the police and told to disconnect them.
I said to the cop "it's only the same as connecting one of those additional brake lights" and he said "DISCONNECT IT". The
w**ker..
[Edited on 28/11/06 by GavBurns]
There is a proviso that the rear fog should not operate as a brake light as the maximum brightness for brake lights is 80 candelas while fog lights
should be maximum 150 candelas on Page 88. Also on page 90 check that the rear fog lamp is fitted with a tell tale light, not operated by a brake
control and is fitted squarely to the rear.
[Edited on 4/12/06 by Peteff]
quote:
Originally posted by Peteff
There is a proviso that the rear fog should not operate as a brake light as the maximum brightness for brake lights is 80 candelas while fog lights should be maximum 150 candelas on Page 88. Also on page 90 check that the rear fog lamp is fitted with a tell tale light, not operated by a brake control and is fitted squarely to the rear.
I suppose I could fit a 'real' fog light mounted squarely on the lower diffuser and let it fall off after SVA. 
For clarification, the lights are
FOG - REVERSE - STOP/TAIL - INDICATOR
[Edited on 4-12-06 by RazMan]
quote:
Originally posted by dave r
am sure that there is a distance that stop/tail lights have to be from the fog lamp ??
I'd say you'll not get away with it at SVA. There is a minimum limit of 100mm between a brake and fog light. The difference in candel power for the same wattage of bulb is due to the reflector that is found in the fog light but not in the brake light (I suspect).
quote:
Originally posted by omega 24 v6
I'd say you'll not get away with it at SVA. There is a minimum limit of 100mm between a brake and fog light.
quote:
Probably safer to mount a semi-permanent fog light until SVA is passed then
Ah but when switched on, the fog light will be 110mm from the outer tail light. When it is switched off it reverts to the tail light again.
My old Nissan had a 3 function rear light - Stop/tail - Fog & Reverse. The reverse light was a ring of white led's that rotated when switched
on too! I made a little magic box that only allowed one function at a time.
I bet it will confuse the SVA man anyway
[Edited on 4-12-06 by RazMan]
Interesting and controversial
Personally with some of the gimps on the road I think It's basically a sound idea. However in some cases it needs to be combined with rear facing
machine guns.
quote:
Originally posted by RazMan
My car has a pair of stop & tail lights and a pair of fog lights. In the interest of safety I wish to make the fog lights double up as stop & tail lights during good weather, with the fog light function kicking in when needed (through some basic electronics)
Maybe I am just a born pioneer 
It just ocurred to me that a very low car is often hard to spot at night unless the lights are mounted higher up. The Focus started a trend in this
area and a lot of cars followed suit. Also why not make things a bit more visible by utilising semi redundant light units (fog & reverse lights)
which are not used 99.9% of the time? The use of basic electronics make this sort of conversion easy too.
Apart from that I am a flash git
quote:
The Focus started a trend in this area
I think you are heading for trouble.
Failed my first sva as the fog / brake light brightnesses were not right. I argued about the bulbs being 21W at which point i had to remove the lenses
of the lights..... at which point MR SVA pointed out that the internal reflectors of a brake light and a fog light are different, and never the two
can be swapped or changed or doubled up.
Essentially stop tail has a satin reflector, fog has a mirror polished job. You will need stand alone reflectors with those lights also.
Thanks for the info James - and on closer inspection it seems that you are correct. The fog reflector is a smooth mirror surface whereas the stop/tail
reflector is muti faceted. The fog light bulb is also much deeper into the reflector which presumeably changes the focus of the light.
Looks like I will have to keep them as single function lights then - ah well.
I am presently converting these lights to the new high power 'Luxeon' leds. These little beauties are rated at 3W and have a much wider
angle of view than conventional leds - I actually think they are brighter than filament bulbs but they need to be positioned further back in the
reflector to make them work well.
They run on next to no current so a good power saving for small alternators.
The pic shows an indicator 'bulb' but they are also available in red stop/tail and white versions (all 3W). The only conventional bulbs on
the car are now just the headlights.
[Edited on 8-12-06 by RazMan]
Rescued attachment 1157_3wled10.jpg