They're distinctly out of fashion but in most cars if you want to see where
you're going when driving fast at night, you'll need them. What are we talking
about? - driving lights. And despite protestations to the contrary, you can
almost forget upgrading the existing bulbs or fitting tiny projection-style
ancillary lights if you want a lot more high beam depth and brightness.
Nope, by far the best way to see further is to fit large, good quality extra lights. If the build quality is there, they don't even have to be all that high
But like all things automotive there are a few aspects to look out for when
buying, and a few tricks to the best installation. And after you've fitted them,
there's one of the most critical steps of all - aiming the lights.
Lights... and Lights
These days with the proliferation of factory foglights - most of which seem
to be switched on at all the wrong times - you could be forgiven for thinking
that extra lights are only for wankers. (After all, even the factory foglights
don't seem to be much better in beam cut-off or penetration than using your
ordinary low beam in the fog!)
In fact, some people call all extra lights 'foglights', being unaware
that ancillary forward-facing lights come in three distinct types:
- Foglights - these have a very low beam cut-off to avoid shining the
light into the fog and dazzling the driver with the reflected light. Their reach
is therefore limited, typically being about 150 metres. Some foglights are
coloured, which further helps reduce dazzling. For driving fast at night in
non-foggy conditions, foglights (whether factory or aftermarket) are useless.
That makes sense - they're not designed for that purpose.
- Driving Lights (cornering) - Cornering lamps aren't just for going
around corners - the broad beam that they provide can also be useful in seeing
any wildlife that is about to step (or hop) onto the road. Cornering lights have
a typical range of about 250 metres.
- Driving Lights (pencil beam) - As the name suggests, these lights have a
long, narrow beam. A good pencil driving light will have a useful range of up to
2000 metres - that's 2 kilometres.... What 'useful range' means in this context is
that you'll be able to pick up roadside reflectors at that sort of distance - on
dead-straight roads, anyway.
A serious night driving set-up might use one cornering beam and one pencil
beam. Since these variations are normally available in identical bodies, the
pair of lights will look much the same, with perhaps just slightly different
lens designs. (Some driving lights are available in all three configurations -
fog, cornering and pencil. So you'd better be sure what you're buying!)
When comparing like with like (light with light?!), the larger the reflector,
the more light that you get out of it. Sure, driving lights come with various
bulb wattages, but going from a 50 to a 100 watt bulb won't make anywhere near
the difference of upsizing from a tiny 50W driving light to a big 50W design.
That doesn't mean that you have to be running a set of lights that look like
they came off a bull-bar at an outback truckstop, but it does mean that if you
reckon that you'll get the equivalent of a pencil beam reach out of a light
smaller than your fist you're fooling yourself. (On any normal kind of budget,
There are plenty of unbranded driving lights around, often at very low
prices. However, for durability and functionality, we highly recommend that you
go only with a major, longstanding brand like Hella, Narva, Cibie, Bosch - or
something similar. Have a look at the brands of lights used by those who really
need them - long-distance trucks and buses are a good starting point.
If you buy a driving light of adequate size and from a good maker, it's
unlikely that you'll need to go super high in wattage. The recommended bulb and
wattage for that lamp should be sufficient. People fitting higher than standard
bulb wattages are really saying that the lens and reflector aren't good
Before you venture to a retailer, work out the general type of light that you
want. Driving lights are available in round and rectangular (and some oval)
designs, but in addition to this they also vary in depth and mounting technique.
Will the light be hung from its mount (pendant style) or will the light be
standing upright? Most driving lights can be easily adapted to either
configuration, but some can't - so you need to know before you go buying. Is a
very thin light required or is mounting depth unlikely to be a problem? What's
the maximum size that you feel comfortable with from an aesthetic point of view?
The more recent the car, the more difficult it will be to visually integrate
the lights. In some cases, if you want large lights you'll need to consider
adding a front nudge bar - there's simply nowhere else to place them! (Using a
nudge bar mounting also reduces radiator blockage, but a couple of big Cibies on
a nudge bar kinda brands you as being a resident of somewhere way out in the red
And of course the dollars and cents come into it, too. The sky's the limit
when it comes to spending money on ancillary lights, what with high-intensity
gas discharge and active cornering light designs available. However, on a saner
plane, you can pay from about AUD$150 to about $250 for a pair of good quality
lights of the sort that we've been describing. If this is too much, look for
secondhand driving lights (although remember to make sure that you're not
getting foglights when you're thinking of driving lights!).
The Hella Comet 450 driving lights shown here were purchased secondhand
(complete with relay and wiring) for AUD$32. They are 100W cornering light units
with a beam reach of about 250 metres and with a wide secondary lighting area.
As such, they are much more suitable for winding roads than for long
Because of the angle that the beam of light makes with the road, the higher
the lights are mounted, the better. However, in practice, mounting the lights
above or below the bumper will make very little difference to the end result.
More important to the positioning are two factors - visual preference and
available mounting points.
Many years ago when all cars had chrome-plated steel bumpers, it was easy -
you drilled a hole in either the top or the bottom of the bumper and bolted the
lights in place. Fifteen minute job. But with plastic-covered bumpers,
integrated brake ducts and undertrays, finding decent mounting points can be
very difficult. Invariably, a pair of custom brackets will need to be made - but
hang in there, most can be formed with just hand tools and some patience.
Another major reason that very firm mountings are needed is that it's
important that the driving light is as rigid as possible. A light that vibrates
- or worse, moves an even greater amount under aerodynamic and vertical loads -
will have a shorter bulb life, in addition to potentially flashing the beam all
over the place.
When selecting a mounting spot, keep in mind that your brackets are most
likely going to need to access existing bodywork bolts that are fairly major in
dimensions. If you can attach the light with a bracket that is secured in place
by only a single 10-mm (socket size) bolt, it's almost a certainty that the
light will vibrate badly. Either multiple 10mm bolts or a single much larger
bolt will need to be used. And why existing bolts? Two reasons - (1) when you
sell the car it will allow the easy removal of the lights without leaving daggy
holes, and (2) an existing bolt is likely to be more rigid than one that you
insert in a hole drilled through some flimsy sheet metal.
Making the Brackets
The Comet 450 driving lights were destined for a first-series Lexus LS400. A
number of mounting positions were considered; locating the lights under the
bumper either side of the numberplate was aesthetically the best. But to find
secure mounts at these locations would have been very involved - for a start,
the bumper cover would have had to have come off. It was instead easier to mount
the lights in front of the grille, which also has the side benefit of giving a
higher mounting point.
The Lexus grille lifts with the bonnet so it was decided that the flat
brackets should protrude from under the grille - that is, the grille would shut
down on the brackets (there's sufficient gap that the grille wouldn't hit the
brackets). Behind the grille were a number of plastic screw plugs that hold the
bumper cover to a metal pressing that runs across above the main structural
bumper beam. The plastic screws weren't ever going to hold anything rigidly in
place, but they popped out to reveal good sized holes through which new bolts
could be inserted. The bracket for one light (always do one at a time!) was bent
up from thick 50 x 4mm aluminium strip and held in place with a spacer and high
tensile bolt. The spotlight mounting bolt needed to be shortened a little to
allow clearance to the opening and closing bonnet, but other than that it was
But actually it wasn't. The bracket was strong but the sheet metal pressing
that it was bolted to wasn't sufficiently rigid - the spotlight could be easily
wobbled by hand. The answer was to make a stiffening piece that ran along the
full length of the metal pressing. Constructed from 25 x 3mm aluminium angle, it
provided extra torsional (twisting) strength, despite the fact that parts of the
alloy angle needed to be cut away to give clearance for the bonnet rubbers and
the bonnet release handle. Note that the aluminium angle also had to be bent to
conform to a slight curve (when viewed from above).
With the strengthening piece bolted into place, the bracket for the spotlight
could again be attached. This time it was remarkably secure. The process now
proved, the second lamp bracket could then be made.
Note that the aluminium brackets and strengthening piece were later painted
black with a spray can.
While if you keep a few things in mind the mechanical fitting of extra lights
is straightforward enough, some people then drop the ball when they get to the
wiring. However, despite the need to use a relay, if you make one vital decision
it can all be pretty simple. The vital decision? That's the one where you decide
that whenever the high beam is on, so are the driving lights. If you configure
the system like this, all the wiring can be done under the bonnet without any
need to run cables back into the cabin - in most modern cars, that makes things
With this approach, power is picked up directly from the positive terminal of
the battery and the relay is triggered straight from one of the high beam power
Note you can always have a switch under the bonnet to disable the new lights,
should a situation develop where when you are running high beam you don't want
the ancillary lights on. (In the real world I have come across that requirement
only once - when the car had a failing alternator and the driving lights were
gradually flattening the battery.)
The first step is to wire the two earths of the driving lights to the body.
Some older designs using metal bodies earth themselves through their mounting
bolts, but with the plethora of plastic in cars it makes sense even in these
designs to run an additional earth from the bodies to the metalwork of the car.
The other wires from each of the lights (ie their power wires) run back to the
relay, connecting to terminal 87. Terminal 30 (the other side of the relay
'switch') connects to the positive of the battery via an in-line fuse holder.
There are a few things to pay attention to when doing this work. Firstly,
always make sure that you use a fuse - without it, any short-circuit that might
develop could lead to a car fire - and that's the case even with the car locked
and you having walked away. Always place the fuse as close to the battery as
practicable. (In the case of the pictured Lexus, I used a panel-mount fuse
holder that I had salvaged from an old domestic hi-fi amplifier.)
wire of adequate gauge for the wiring discussed so far. The wire from the
battery to the fuse holder and then to the relay needs to carry all the current
that the two lights will draw. That could be as high as 15 amps - make sure that
the wire is rated to suit.
You'll need to make a connection to the high-beam wiring to provide the
switch-on signal for the relay. Use a multimeter to probe the back of the
headlight until you find a wire that has 12V on it when the high beam is on -
and 0V when it is off. If the car uses a separate high beam light within the
headlight assembly, finding this wire will be easier. Tap into the high beam
power supply wire and then run the new wire to terminal 85 of the relay.
Terminal 86 (the other side of the relay's coil) then gets connected to earth.
[In some cars, power is always fed to the high beam, with the factory
switching working by earthing the light to turn it on. In cars where the wiring
is like this (you'll soon know because you won't be able to find a 12V at the
light that ever goes off) just wire the relay coil in parallel with the high
beam. The other connections remain the same.]
The way the system works is this. When you turn on high beam, power also
flows through the relay's coil, creating a magnetic field which pulls the relay
contact over. This allows power to flow from the battery to the fuse to the
driving lights, turning them on.
If you want to put a switch in the circuit, place it in between the headlight
high beam power pick-up and the relay, ie break the wire heading to terminal 85
and put it in there. Note that unlike the power feed for the driving lights,
these wires can be quite thin in gauge without any problems being caused.
These instructions refer to traditional car lighting. If your car has high
intensity discharge (HID) lighting you should not probe into the wiring
of the system. Dangerously high voltages are present in these systems.
So you've bolted on the driving lights and wired them up. Think you're now
finished? Wrong! Aiming of the lights is one of the most important steps in
What you need is a dark (duh!) empty and straight road, preferable with
roadside reflectors. You'll also need two people, one to adjust the lights and
the other to sit in the driver's seat and call the shots.
The actual process is pretty simple. With the car idling and in a normal
position on the road, adjust each light until the beam reach and illumination is
best. Typically, that will mean starting with the lights too high then gradually
dropping them down in aim until distant reflectors start to be highlighted -
then down just a fraction more. The driver's side light should be aimed down the middle of the road while the passenger side light should be angle a
little more towards the edge of the road.
Incorrect aim - especially of pencil beams - can make the difference between
having fantastic additions or having lights that you may as well not bothered
fitting. The difference can be that great.
If you buy carefully and fit them correctly, driving lights can make a huge
difference to night-time country road visibility. The cost doesn't have to be
very high and the results are typically vastly superior to changing the bulb
design and/or wattage of the original headlights.