LED light bars have become one of the most popular accessories bolted to a 4WD today, and for good reason. They are cheap, put out a heap of light, don’t weigh too much and realistically are quite compact.
One of the more common places to mount an LED light bar is on the roof of a 4WD, as it doesn’t restrict air flow into the motor, can be the full width of the vehicle and gives you a bit more depth as the light is further back than if it were on the front of your vehicle. The unfortunate thing about mounting an LED light bar on the roof is that if you don’t do it correctly, you’ll end up with it shining on the bonnet.
If you’ve never experienced this, you might think its not much of a big deal, but I promise you, its incredibly dangerous (and actually illegal). Light bars are insanely bright, and anything that reflects off is going to hurt. We run a 42 inch Stedi light bar on the top of our Dmax, and big street signs are a total nightmare.
I made sure that when it was installed it was physically impossible to shine on the bonnet, and in actual fact this is very easy to do.
How do you stop the light bar from shining on the bonnet?
Position it correctly
The easiest way to guarantee you’ll have no reflection from your bonnet or bull bar is to mount it so the light cannot physically shine onto them. Take a look at the photo below, and you’ll see an imaginary line (or you can run a piece of rope or string to get the same effect) from the front of your bull bar, to where the roof line starts.
Any lights you mount on the roof need to be under this line. By doing this, you rely on the roof to physically stop any light getting to the bonnet or bull bar, and your reflections will be zero, with exception of antennas and sometimes your normal side mirrors.
The further back you mount the bar, the higher it needs to be as you’ll find the roof will block a significant portion of the light out. Its actually really easy to do – wire your LED light bar up with a long lead, park it somewhere that you aren’t going to annoy anyone at night (your driveway, or in the bush) and move the bar around to see where the light is best.
Ours is mounted on top of the Bull Motor Body canopy, about 300mm higher than the roof height of the Dmax, and probably 2/3 of the way back from the start of the vehicle, and it works brilliantly.
Install a deflector
Unfortunately, its not always possible to mount the LED light bar back further. This is especially the case if you’ve bought mounts that attach to the top of the pillar, or on front of a full length bull bar. If you have no choice but to have the bar forward, you either get rid of it completely, or you can install a deflector.
This can be as simple as a piece of aluminium flat bar glued to the bottom of the light bar, which sticks out roughly 10mm (or more depending on the light location setup). Any light that heads down towards the bonnet hits the bit of aluminium instead, and you get to enjoy nice driving lights without getting blinded from the bonnet
Wrapping or painting the bonnet
I have seen a few people wrap, or paint their bonnet due to the reflections from a light bar. This would be an absolute last resort, and not something I would do. By law the lights shouldn’t impede your vision, which this doesn’t fix. It just masks the issue.
Can you mount LED light bars on the roof?
Of course, before you do any of this, make sure you are legally allowed to run LED Light bars on the roof. In WA you were not allowed to for a number of years, and that decision has been reversed, allowing it to be done. Otherwise, this forms 32 ways to make your 4WD illegal.